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+<pre>
+
+Project Gutenberg's Gas-Engines and Producer-Gas Plants, by R. E. Mathot
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+Title: Gas-Engines and Producer-Gas Plants
+       A Practice Treatise Setting Forth the Principles of
+              Gas-Engines and Producer Design, the Selection and
+              Installation of an Engine, Conditions of Perfect Operation,
+              Producer-Gas Engines and Their Possibilities, the Care of
+              Gas-Engines and Producer-Gas Plants, with a Chapter on
+              Volatile Hydrocarbon and Oil Engines
+
+Author: R. E. Mathot
+
+Commentator: Dugald Clerk
+
+Translator: Waldemar Kaempffert
+
+Release Date: December 26, 2011 [EBook #38415]
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+*** START OF THIS PROJECT GUTENBERG EBOOK GAS-ENGINES, PRODUCER-GAS PLANTS ***
+
+
+
+
+Produced by Erik Reh, Henry Gardiner and the Online
+Distributed Proofreading Team at https://www.pgdp.net
+
+
+
+
+
+
+</pre>
+
+
+<div class="center" style="width: 25em; margin: auto; border: solid 1px; padding: 1em;">
+Transcriber's Note: The original publication has been replicated faithfully except as listed
+<a href="#Corrections" name="Start" id="Start">here</a>.
+</div>
+
+<hr class="ChapterTopRule" />
+<!--003.png-->
+
+<h1>Gas-Engines and<br />
+Producer-Gas Plants</h1>
+
+<div style="font-size:smaller; text-align:center">
+A PRACTICE TREATISE SETTING FORTH THE PRINCIPLES
+OF GAS-ENGINES AND PRODUCER DESIGN, THE
+SELECTION AND INSTALLATION OF AN ENGINE, CONDITIONS
+OF PERFECT OPERATION, PRODUCER-GAS
+ENGINES AND THEIR POSSIBILITIES, THE CARE OF GAS-ENGINES
+AND PRODUCER-GAS PLANTS, WITH A CHAPTER
+ON VOLATILE HYDROCARBON AND OIL ENGINES</div>
+
+<div class="c4">BY</div>
+<div class="c3">R. E. MATHOT, M.E.</div>
+
+<div class="c5">Member of the Soci&eacute;t&eacute; des Ing&eacute;nieurs Civils de France, Institution of
+Mechanical Engineers, Association des Ing&eacute;nieurs de
+l'Ecole des Mines du Hainaut of Brussels</div>
+
+<div class="c4">TRANSLATED FROM ORIGINAL FRENCH MANUSCRIPT BY</div>
+<div class="c3">WALDEMAR B. KAEMPFFERT</div>
+
+<div class="c4">WITH A PREFACE BY</div>
+<div class="c3">DUGALD CLERK, <span class="smcap">M. Inst.</span> C.E., F.C.S.</div>
+
+<div class="c4">ILLUSTRATED</div>
+
+<hr style="width: 35%;" />
+<div class="c4">NEW YORK</div>
+<div class="c3">MUNN &amp; COMPANY</div>
+<div class="c3">OFFICE OF THE SCIENTIFIC AMERICAN</div>
+<div class="c3">361 BROADWAY</div>
+<div class="c3">1905</div>
+
+<hr class="ChapterTopRule" />
+<!--005.png--><p><span class='pagenum'><a name="Page_5" id="Page_5"></a></span></p>
+<h2>PREFACE</h2>
+<div class="c3">TO</div>
+
+<div class="c2">"MATHOT'S GAS-ENGINES AND
+PRODUCER-GAS PLANTS"</div>
+
+<div class="c3">BY</div>
+
+<div class="c3"><span class="smcap">Dugald Clerk, M. Inst.C.E., F.C.S.</span></div>
+
+<p>Mr. Mathot, the author of this interesting work,
+is a well-known Belgian engineer, who has devoted
+himself to testing and reporting upon gas and oil
+engines, gas producers and gas plants generally for
+many years past. I have had the pleasure of knowing
+Mr. Mathot for many years, and have inspected gas-engines
+with him. I have been much struck with the ability
+and care which he has devoted to this subject.
+I know of no engineer more competent to deal with
+the many minute points which occur in the installation
+and running of gas and oil engines. I have read this
+book with much interest and pleasure, and I consider
+that it deals effectively and fully with all the principal
+detail points in the installation, operation, and testing
+of these engines. I know of no work which has gone
+so fully into the details of gas-engine installation and
+up-keep. The work clearly points out all the matters
+which have to be attended to in getting the best work
+<!--006.png--><span class='pagenum'>vi</span>
+from any gas-engine under the varying circumstances
+of different installations and conditions. In my view,
+the book is a most useful one, which deserves, and no
+doubt will obtain, a wide public recognition.</p>
+
+<div class="right"><span class="smcap">Dugald Clerk.</span></div>
+
+<p><i>March, 1905.</i></p>
+
+<hr class="ChapterTopRule" />
+<!--007.png--><p><span class='pagenum'>vii</span></p>
+
+<h2>INTRODUCTION</h2>
+
+<p>The constantly increasing use of gas-engines in the last decade has led
+to the invention of a great number of types, the operation and care of
+which necessitate a special practical knowledge that is not exacted by
+other motors, such as steam-engines.</p>
+
+<p>Explosion-engines, driven by illuminating-gas, producer-gas, oil,
+benzin, alcohol and the like, exact much more care in their operation
+and adjustment than steam-engines. Indeed, steam-engines are regularly
+subjected to comparatively low pressures. The temperature in the
+cylinders, moreover, is moderate.</p>
+
+<p>On the other hand, the explosion-motor is irregularly subjected to high
+and low pressures. The temperature of the gases at the moment of
+explosion is exceedingly high. It is consequently necessary to resort to
+artificial means for cooling the cylinder; and the manner in which this
+cooling is effected has a very great influence on the operation of the
+motor. If the cooling be effected too rapidly, the quantity of gas
+consumed is considerably increased; if the cooling be effected too
+slowly, the motor parts will quickly deteriorate.</p>
+
+<p>In order to reduce the gas consumption to a minimum, a matter which is
+particularly important when
+<!--008.png--><span class='pagenum'>viii</span>
+the motor is driven by street-gas, the
+explosive mixture is compressed before ignition. Only if all the parts
+are built with joints absolutely gas-tight is it possible to obtain this
+compression. The slightest leakage past the valves or around the piston
+will sensibly increase the consumption.</p>
+
+<p>The mixture should be exploded at the exact moment the piston starts on
+its working stroke. If ignition occurs too soon or too late, the result
+will be a marked diminution in the useful effect produced by the
+expansion of the gas. All ignition devices are composed of delicate
+parts, which cannot be too well cared for.</p>
+
+<p>It follows from what has thus far been said that the causes of
+perturbation are more numerous in a gas than in a steam engine; that
+with a gas-engine, improper care will lead to a much greater increase in
+consumption than with a steam-engine, and will cause a waste in power
+which would hardly be appreciable in steam-engines, whether their joints
+be tight or not.</p>
+
+<p>It is the purpose of this manual to indicate the more
+elementary precautions to be taken in the care of an engine operating
+under normal conditions, and to explain how repairs should be made to
+remedy the injuries caused by accidents. Engines which are of less than
+200 horse-power and which are widely used in a small way will be
+primarily considered. In another work the author will discuss more
+powerful engines.</p>
+
+<p>Before considering the choice, installation, and operation of a
+gas-engine, it will be of interest to ascertain
+<!--009.png--><span class='pagenum'>ix</span>
+the relative cost of
+different kinds of motive power. Disregarding special reasons which may
+favor the one or the other method of generating power, the net cost per
+horse-power hour will be considered in each case in order to show which
+is the least expensive method of generating power in ordinary
+circumstances.</p>
+
+<p class="right" style="font-size: 0.8em">R. E. MATHOT.</p>
+
+<p><span class="smcap" style="font-size: 0.8em">March, 1905.</span></p>
+
+<!--010.png--><p><span class='pagenum'>x</span></p>
+
+<hr class="ChapterTopRule" />
+<!--011.png--><p><span class='pagenum'>xi</span></p>
+
+<h2>TABLE OF CONTENTS</h2>
+
+<table border="0" width="80%" summary="Contents">
+<tr>
+  <td></td>
+  <td class="toctd4" style="font-size: 0.8em">PAGE</td>
+</tr>
+<tr>
+  <td class="toctd1"><a href="#CHAPTER_I">CHAPTER I</a></td>
+</tr>
+<tr>
+  <td class="toctd2">MOTIVE POWER AND COST OF INSTALLATION</td>
+  <td class="toctd4">17</td>
+</tr>
+<tr>
+  <td class="toctd1"><a href="#CHAPTER_II">CHAPTER II</a></td>
+</tr>
+<tr>
+  <td class="toctd2">SELECTION OF AN ENGINE</td>
+</tr>
+<tr>
+  <td class="toctd3">
+    The Otto Cycle.&mdash;The First Period.&mdash;The Second Period.&mdash;The
+    Third Period.&mdash;The Fourth Period.&mdash;Valve Mechanism.&mdash;Ignition.&mdash;Incandescent
+    Tubes.&mdash;Electric Ignition.&mdash;Electric Ignition by Battery and
+    Induction-Coil.&mdash;Ignition by Magnetos.&mdash;The Piston.&mdash;Arrangement
+    of the Cylinder.&mdash;The Frame.&mdash;Fly-Wheels.&mdash;Straight and Curved
+    Spoke Fly-Wheels.&mdash;The Crank-Shaft.&mdash;Cams, Rollers,
+    etc.&mdash;Bearings.&mdash;Steadiness.&mdash;Governors.&mdash;Vertical Engines.&mdash;Power
+    of an Engine.&mdash;Automatic Starting
+  </td>
+  <td class="toctd4">21</td>
+</tr>
+<tr>
+  <td class="toctd1"><a href="#CHAPTER_III">CHAPTER III</a></td>
+</tr>
+<tr>
+  <td class="toctd2">THE INSTALLATION OF AN ENGINE</td>
+</tr>
+<tr>
+  <td class="toctd3">
+  Location.&mdash;Gas-Pipes.&mdash;Dry Meters.&mdash;Wet Meters.&mdash;Anti-Pulsators,
+  Bags, Pressure-Regulators.&mdash;Precautions.&mdash;Air Suction.&mdash;Exhaust.&mdash;Legal
+  Authorization
+  </td>
+  <td class="toctd4">69</td>
+</tr>
+<tr>
+  <td class="toctd1"><a href="#CHAPTER_IV">CHAPTER IV</a></td>
+</tr>
+<tr>
+  <td class="toctd2">FOUNDATION AND EXHAUST</td>
+</tr>
+<tr>
+  <td class="toctd3">
+  The Foundation Materials.&mdash;Vibration.&mdash;Air Vibration, etc.&mdash;Exhaust
+  Noises</td>
+  <td class="toctd4">87</td>
+</tr>
+<!--012.png--><tr><td><span class='pagenum'>xii</span></td></tr>
+<tr>
+  <td class="toctd1"><a href="#CHAPTER_V">CHAPTER V</a></td>
+</tr>
+<tr>
+  <td class="toctd2">WATER CIRCULATION</td>
+</tr>
+<tr>
+  <td class="toctd3">
+  Running Water.&mdash;Water-Tanks.&mdash;Coolers
+  </td>
+  <td class="toctd4">98</td>
+</tr>
+<tr>
+  <td class="toctd1"><a href="#CHAPTER_VI">CHAPTER VI</a></td>
+</tr>
+<tr>
+  <td class="toctd2">LUBRICATION</td>
+</tr>
+<tr>
+  <td class="toctd3">
+  Quality of Oils.&mdash;Types of Lubricators
+  </td>
+  <td class="toctd4">111</td>
+</tr>
+<tr>
+  <td class="toctd1"><a href="#CHAPTER_VII">CHAPTER VII</a></td>
+</tr>
+<tr>
+  <td class="toctd2">CONDITIONS OF PERFECT OPERATION</td>
+</tr>
+<tr>
+  <td class="toctd3">
+  General Care.&mdash;Lubrication.&mdash;Tightness of the
+  Cylinder.&mdash;Valve-Regrinding.&mdash;Bearings.&mdash;Crosshead.&mdash;Governor.&mdash;Joints.&mdash;Water
+  Circulation.&mdash;Adjustment
+  </td>
+  <td class="toctd4">121</td>
+</tr>
+<tr>
+  <td class="toctd1"><a href="#CHAPTER_VIII">CHAPTER VIII</a></td>
+</tr>
+<tr>
+  <td class="toctd2">HOW TO START AN ENGINE.&mdash;PRELIMINARY PRECAUTIONS</td>
+</tr>
+<tr>
+  <td class="toctd3">
+  Care during Operation.&mdash;Stopping the Engine
+  </td>
+  <td class="toctd4">128</td>
+</tr>
+<tr>
+  <td class="toctd1"><a href="#CHAPTER_IX">CHAPTER IX</a></td>
+</tr>
+<tr>
+  <td class="toctd2">
+  PERTURBATIONS IN THE OPERATION OF ENGINES AND
+  THEIR REMEDY</td>
+</tr>
+<tr>
+  <td class="toctd3">
+  Difficulties in Starting.&mdash;Faulty Compression.&mdash;Pressure of Water in
+  the Cylinder.&mdash;Imperfect Ignition.&mdash;Electric Ignition by Battery or
+  Magneto.&mdash;Premature Ignition.&mdash;Untimely Detonations.&mdash;Retarded
+  Explosions.&mdash;Lost Motion in Moving Parts.&mdash;Overheated
+  Bearings.&mdash;Overheating of the Cylinder.&mdash;Overheating of the
+  Piston.&mdash;Smoke arising from the Cylinder.&mdash;Back Pressure to the
+  Exhaust.&mdash;Sudden Stops
+  </td>
+  <td class="toctd4">134</td>
+</tr>
+<tr><td><!--013.png--><span class='pagenum'>xiii</span></td></tr>
+<tr>
+  <td class="toctd1"><a href="#CHAPTER_X">CHAPTER X</a></td>
+</tr>
+<tr>
+  <td class="toctd2">PRODUCER-GAS ENGINES</td>
+</tr>
+<tr>
+  <td class="toctd3">
+  High Compression.&mdash;Cooling.&mdash;Premature Ignition.&mdash;The Governing
+  of Engines
+  </td>
+  <td class="toctd4">153</td>
+</tr>
+<tr>
+  <td class="toctd1"><a href="#CHAPTER_XI">CHAPTER XI</a></td>
+</tr>
+<tr>
+  <td class="toctd2">PRODUCER-GAS</td>
+</tr>
+<tr>
+  <td class="toctd3">
+  Street-Gas.&mdash;Composition of Producer-Gases.&mdash;Symptoms of
+  Asphyxiation.&mdash;Gradual, Rapid Asphyxiation.&mdash;Slow, Chronic
+  Asphyxiation.&mdash;First Aid in Cases of Carbon Monoxide
+  Poisoning.&mdash;Sylvester Method.&mdash;Pacini Method.&mdash;Impurities of
+  the Gases
+  </td>
+  <td class="toctd4">165</td>
+</tr>
+<tr>
+  <td class="toctd1"><a href="#CHAPTER_XII">CHAPTER XII</a></td>
+</tr>
+<tr>
+  <td class="toctd2">PRESSURE GAS-PRODUCERS</td>
+</tr>
+<tr>
+  <td class="toctd3">
+  Dowson Producer.&mdash;Generators.&mdash;Air-Blast.&mdash;
+  Blowers.&mdash;Fans.&mdash;Compressors.&mdash;Exhausters.&mdash;Washing
+  and Purifying.&mdash;Gas-Holder.&mdash;Lignite and Peat
+  Producers.&mdash;Distilling-Producers.&mdash;Producers Using Wood Waste, Sawdust,
+  and the like.&mdash;Combustion-Generators.&mdash;Inverted Combustion
+  </td>
+  <td class="toctd4">174</td>
+</tr>
+<tr>
+  <td class="toctd1"><a href="#CHAPTER_XIII">CHAPTER XIII</a></td>
+</tr>
+<tr>
+  <td class="toctd2">SUCTION GAS-PRODUCERS</td>
+</tr>
+<tr>
+  <td class="toctd3">
+  Advantages.&mdash;Qualities of Fuel.&mdash;General
+  Arrangement.&mdash;Generator.&mdash;Cylindrical Body.&mdash;Refractory
+  Lining.&mdash;Grate and Support for the
+  Lining.&mdash;Ash-pit.&mdash;Charging-Box.&mdash;Slide-Valve.&mdash;Cock.&mdash;Feed-Hopper.&mdash;Connection
+  of Parts.&mdash;Air Supply.&mdash;Vaporizer.&mdash;Preheaters.&mdash;Internal
+  Vaporizers.&mdash;External Vaporizers.&mdash;Tubular Vaporizers.&mdash;Partition
+  Vaporizers.&mdash;Operation of the Vaporizers.&mdash;Air-Heaters.&mdash;Dust-Collectors.&mdash;Cooler,
+  Washer, Scrubber.&mdash;Purifying Apparatus.&mdash;Gas-Holders.&mdash;Drier.&mdash;Pipes.&mdash;
+  Purifying-Brush.&mdash;Conditions
+  <!--014.png--><span class='pagenum'>xiv</span>
+  of Perfect Operation of Gas-Producers.&mdash;Workmanship
+  and System.&mdash;Generator.&mdash;Vaporizer.&mdash;Scrubber.&mdash;Assembling the
+  Plant.&mdash;Fuel.&mdash;How to Keep the Plant in Good Condition.&mdash;Care
+  of the Apparatus.&mdash;Starting the Fire for the Gas-Producer.&mdash;Starting
+  the Engine.&mdash;Care of the Generator during Operation.&mdash;Stoppages
+  and Cleaning
+  </td>
+  <td class="toctd4">199</td>
+</tr>
+<tr>
+  <td class="toctd1"><a href="#CHAPTER_XIV">CHAPTER XIV</a></td>
+</tr>
+<tr>
+  <td class="toctd2">OIL AND VOLATILE HYDROCARBON ENGINES</td>
+</tr>
+<tr>
+  <td class="toctd3">
+  Oil-Engines.&mdash;Volatile Hydrocarbon Engines.&mdash;Comparative Costs.&mdash;Tests
+  of High-Speed Engines.&mdash;The Manograph.&mdash;The Continuous
+  Explosion-Recorder for High-Speed Engines.&mdash;Records
+  </td>
+  <td class="toctd4">264</td>
+</tr>
+<tr>
+  <td class="toctd1"><a href="#CHAPTER_XV">CHAPTER XV</a></td>
+</tr>
+<tr>
+  <td class="toctd2">THE SELECTION OF AN ENGINE</td>
+</tr>
+<tr>
+  <td class="toctd3">
+  The Duty of a Consulting Engineer.&mdash;Specifications.&mdash;Testing the
+  Plant.&mdash;Explosion-Recorder for Industrial Engines.&mdash;Analysis of
+  the Gases.&mdash;Witz Calorimeter.&mdash;Maintenance of Plants.&mdash;Test of
+  Stockport Gas-Engine with Dowson Pressure Gas-Producer.&mdash;Test
+  of a Winterthur Engine.&mdash;Test of a Winterthur Producer-Gas
+  Engine.&mdash;Test of a Deutz Producer-Gas Engine and Suction
+  Gas-Producer.&mdash;Test of a 200-H.P. Deutz Suction Gas-Producer and
+  Engine
+  </td>
+  <td class="toctd4">279</td>
+</tr>
+</table>
+
+<hr class="ChapterTopRule" />
+<!--017.png--><p><span class='pagenum'><a name="Page_17" id="Page_17">[17]</a></span></p>
+
+<h2><a name="CHAPTER_I" id="CHAPTER_I"></a>CHAPTER I</h2>
+
+<div class="c3">MOTIVE POWER&mdash;COST OF INSTALLATION</div>
+
+<p>The ease with which a gas-engine can be installed,
+compared with a steam-engine is self-evident. In
+places where illuminating gas can be obtained and
+where less than 10 to 15 horse-power is needed, street-gas
+is ordinarily employed.<a name="FNanchor_A_1" id="FNanchor_A_1"></a>
+<a href="#Footnote_A_1" class="fnanchor">[A]</a> The improvements which
+have very recently been made in the construction of
+suction gas-generators, however, would seem to augur
+well for their general introduction in the near future,
+even for very small powers.</p>
+
+<p>The installation of small street-gas-engines involves
+simply the making of the necessary connections with
+gas main and the mounting of the engine on a small
+base.</p>
+
+<p>An economical steam-engine of equal power would
+necessitate the installation of a boiler and its setting,
+the construction of a smoke-stack, and other accessories,
+while the engine itself would require a firm
+base. Without exaggeration it may be asserted that
+the installation of a steam-engine and of its boiler requires
+five times as much time and trouble as the installation
+of a gas-engine of equal power, without
+considering even the requirements imposed by storing
+the fuel (Fig. 1). Small steam-engines mounted on
+<!--019.png--><span class='pagenum'><a name="Page_19" id="Page_19">[19]</a></span>
+their own boilers, or portable engines, the consumption
+of which is generally not economical, are not here
+taken into account.</p>
+
+<div class="figcenter" style="width: 400px;">
+<img src="images/fig_001.jpg" width="400" height="207" alt="Fig. 1." title="" />
+<span class="caption"><span class='smcap'>Fig. 1.</span>&mdash;30
+H.P. Gas-engine and suction gas-producer.</span>
+</div>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_001a.jpg" width="600" height="353" alt="Fig. 1a." title="" />
+<span class="caption"><span class='smcap'>Fig. 1<i>a</i>.</span>&mdash;30
+H.P. Steam-engine, boiler and smoke-stack.</span>
+</div>
+
+<p>So far as the question of cost is concerned, we find
+that a 15 to 20 horse-power steam-engine working at
+a pressure of 90 pounds and having a speed of 60 revolutions
+per minute would cost about 16<sup>2</sup>&frasl;<sub>3</sub> per cent.
+more than a 15 horse-power gas-engine, with its anti-pulsators
+and other accessories. The foundation of
+the steam-engine would likewise cost about 16<sup>2</sup>&frasl;<sub>3</sub> per
+cent. more than that of the gas-engine. Furthermore
+the installation of the steam-engine would mean the
+buying of piping, of a boiler of 100 pounds pressure,
+and of firebrick, and the erection of a smoke-stack having
+a height of at least 65 feet. Beyond a little excavating
+for the engine-base and the necessary piping, a
+gas-engine imposes no additional burdens. It may be
+safely accepted that the steam-engine of the power
+indicated would cost approximately 45 per cent. more
+than the gas-engine of corresponding power.</p>
+
+<p>The cost of running a 15 to 20 horse-power steam-engine
+is likewise considerably greater than that of
+running a gas-engine of the same size. Considering
+the fuel-consumption, the cost of the lubricating oil
+employed, the interest on the capital invested, the cost
+of maintenance and repair, and the salary of an engineer,
+it will be found that the operation of the steam-engine
+is more expensive by about 23 per cent.</p>
+
+<p>This economical advantage of the gas over the steam-engine
+holds good for higher power as well, and becomes
+<!--020.png--><span class='pagenum'>20</span>
+even more marked when producer-gas is used
+instead of street-gas. Comparing, for example, a 50
+horse-power steam-engine having a pressure of 90
+pounds and a speed of 60 revolutions per minute, with
+a 50 horse-power producer-gas engine, and considering
+in the case of the steam-engine the cost of a boiler of
+suitable size, foundation, firebrick, smoke-stack, etc.,
+and in the case of the gas-engine the cost of the producer,
+foundation, and the like, it will be found that
+the installation of a steam-engine entails an expenditure
+15 per cent. greater than in the case of the producer-gas
+engine. However, the cost of operating and
+maintaining the steam-engine of 50 horse-power will
+be 40 per cent. greater than the operation and maintenance
+of the producer-gas engine.</p>
+
+<p>From the foregoing it follows that from 15 to 20
+up to 500 horse-power the engine driven by producer-gas
+has considerably the advantage over the steam-engine
+in first cost and maintenance. For the development
+of horse-powers greater than 500, the employment
+of compound condensing-engines and engines driven by
+superheated steam considerably reduces the consumption,
+and the difference in the cost of running a steam- and
+gas-engine is not so marked. Still, in the present
+state of the art, superheated steam installations entail
+considerable expense for their maintenance and repair,
+thereby lessening their practical advantages and rendering
+their use rather burdensome.</p>
+
+<div class="c3">FOOTNOTES:</div>
+
+<div class="footnote"><p><a name="Footnote_A_1" id="Footnote_A_1"></a>
+<a href="#FNanchor_A_1"><span class="label">[A]</span></a> Recent improvements
+made in suction gas-producers will
+probably lead to the wide introduction of producer gas engines even
+for small power.</p></div>
+
+<hr class="ChapterTopRule" />
+<!--021.png--><p><span class='pagenum'><a name="Page_21" id="Page_21">[21]</a></span></p>
+<h2><a name="CHAPTER_II" id="CHAPTER_II"></a>CHAPTER II</h2>
+
+<div class="c3">THE SELECTION OF AN ENGINE</div>
+
+<p>Explosion-engines are of many types. Gas-engines,
+of the four-cycle type, such as are industrially
+employed, will here be principally considered.</p>
+
+<p><b>The Otto Cycle.&mdash;</b>The term "four-cycle" motor, or
+Otto engine, has its origin in the manner in which the
+engine operates. A complete cycle comprises four distinct
+periods which are diagrammatically reproduced
+in the accompanying drawings.</p>
+
+<p><b>The First Period.&mdash;</b><i>Suction:</i> The piston is driven
+forward, creating a vacuum in the cylinder, and simultaneously
+drawing in a certain quantity of air and gas
+(Fig. 2).</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_002.jpg" width="600" height="174" alt="Fig. 2." title="" />
+<span class="caption"><span class='smcap'>Fig. 2.</span>&mdash;First cycle: Suction.</span>
+</div>
+
+<p><b>The Second Period.&mdash;</b><i>Compression:</i> The piston returns
+to its initial position. All admission and exhaust
+valves are closed (Fig. 3). The mixture drawn in
+during the first period is compressed.
+<!--022.png--><span class='pagenum'><a name="Page_22" id="Page_22">[22]</a></span></p>
+
+<p><b>The Third Period.&mdash;</b><i>Explosion and Expansion:</i> When
+the piston has reached the end of its return stroke, the
+compressed mixture is ignited. Explosion takes place
+at the dead center. The expansion of the gas drives the
+piston forward (Fig. 4).</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_003.jpg" width="600" height="170" alt="Fig. 3." title="" />
+<span class="caption"><span class='smcap'>Fig. 3.</span>&mdash;Second cycle: Compression.</span>
+</div>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_004.jpg" width="600" height="165" alt="Fig. 4." title="" />
+<span class="caption"><span class='smcap'>Fig. 4.</span>&mdash;Third cycle: Explosion and expansion.</span>
+</div>
+
+<p><b>The Fourth Period.&mdash;</b><i>Exhaust:</i> The piston returns
+a second time. The exhaust-valve is opened, and the
+products of combustion are discharged (Fig. 5).</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_005.jpg" width="600" height="178" alt="Fig. 5." title="" />
+<span class="caption"><span class='smcap'>Fig. 5.</span>&mdash;Fourth cycle: Exhaust.</span>
+</div>
+
+<p>These various cycles succeed one another, passing
+through the same phases in the same order.
+<!--023.png--><span class='pagenum'><a name="Page_23" id="Page_23">[23]</a></span></p>
+
+<p><b>Valve Mechanism.&mdash;</b>It is to be noted that in modern
+motors valves are used which are better adapted to
+the peculiarities of explosion-engines than were the
+old slide-valves used when the Otto engine was first
+introduced. The slide-valve may now be considered
+as an antiquated distributing device with which it is
+impossible to obtain a low consumption.</p>
+
+<p>In old-time gas-engines rather low compressions were
+used. Consequently a very low explosive power of the
+gaseous mixture, and low temperatures were obtained.
+The slide-valves were held to their seats by the pressure
+of external springs, and were generously lubricated.
+Under these conditions they operated regularly.
+Nowadays, the necessity of using gas-engines which are
+really economical has led to the use of high compressions
+with the result that powerful explosions and high
+temperatures are obtained. Under these conditions
+slide-valves would work poorly. They would not be
+sufficiently tight. To lubricate them would be difficult
+and ineffective. Furthermore, large engines are widely
+used in actual practice, and with these motors the frictional
+resistance of large slide-valves, moving on extensive
+surfaces would be considerable and would appreciably
+reduce the amount of useful work performed.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_006.jpg" width="600" height="474" alt="Fig. 6." title="" />
+<span class="caption"><span class='smcap'>Fig. 6.</span>&mdash;Modern valve mechanism.</span>
+</div>
+
+<p>By reason of its peculiar operation, the slide-valve
+is objectionable, the gases being throttled at the time of
+their admission and discharge. As a result of these objections
+there are losses in the charge; and obnoxious
+counter-pressures occur. The necessity of using elements
+simple in their operation and free from the objections
+<!--024.png--><span class='pagenum'><a name="Page_24" id="Page_24">[24]</a></span>
+which have been mentioned, has naturally led
+to the adoption of the present valve. This valve is used
+both for the suction of the gas and of the air, as well as
+for the exhaust, with the result that either of these two
+essential phases in the operation of the motor can be
+independently controlled. The valves offer the following
+advantages: Their tightness increases with the pressure,
+since they always open toward the interior of the
+cylinder (Fig. 6). They have no rubbing surfaces,
+and need not, therefore, be lubricated. Their opening
+is controlled by levers provided with quick-acting
+cams; and their closure is effected by coiled springs
+almost instantaneous in their action (Fig. 7). Each
+valve, depending upon the purpose for which it is used,
+can be mounted in that part of the cylinder best suited
+for its particular function. The types of valved motors
+now used are many and various. In order to attain
+<!--025.png--><span class='pagenum'><a name="Page_25" id="Page_25">[25]</a></span>
+economy in consumption and regularity in operation
+they should meet certain essential requirements which
+will here be reviewed.</p>
+
+<p>Apart from proportioning the areas properly and
+from providing a suitable means of operation, it is indispensable
+that the valves should be readily accessible.
+Indeed, the valves should be regularly examined,
+cleaned and ground. It follows that it should be possible
+to take them apart easily and quickly.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_007.jpg" width="600" height="612" alt="Fig. 7." title="" />
+<span class="caption"><span class='smcap'>Fig. 7.</span>&mdash;Controlling mechanism of valve.</span>
+</div>
+
+<p>It is necessary that the exhaust-valve be well cooled;
+otherwise the valve, exposed as it is to high temperatures,
+will suffer derangement and may cause leakage.
+The water-jacket should, therefore, surround the seat
+of the exhaust-valve, care being taken that the cooling
+water be admitted as near to it as possible (Fig. 8).
+The motor should control the air-let valve or that of
+the gaseous mixture. Hence these valves should not
+<!--026.png--><span class='pagenum'><a name="Page_26" id="Page_26">[26]</a></span>
+be actuated simply by springs, because springs are apt
+to move under the influence of the vacuum produced
+by suction.</p>
+
+<div class="figcenter" style="width: 445px;">
+<img src="images/fig_008.jpg" width="445" height="600" alt="Fig. 8." title="" />
+<span class="caption"><span class='smcap'>Fig. 8.</span>&mdash;Water-jacketed valve.</span>
+</div>
+
+<p>The mixture of gas and air should not be admitted
+into the cylinder at too low a pressure; otherwise the
+weight of the mixture admitted would be lower than it
+<!--027.png--><span class='pagenum'><a name="Page_27" id="Page_27">[27]</a></span>
+ought to be, inasmuch as under these conditions the
+valve will be opened too tardily and closed prematurely.
+At the beginning as well as at the end of its
+stroke the linear velocity of the piston is quite inadequate
+to create a vacuum sufficient to overcome the resistance
+of the spring. It is, therefore, generally the
+practice separately to control the opening or closing of
+the one or the other valve (gas-valve or mixture-valve).
+Consequently these valves must be actuated independently
+of each other. Nowadays they are mechanically
+controlled almost exclusively,&mdash;a method which is advocated
+by well-known designers for industrial motors
+in particular. Valves which are not actuated in this
+manner (free valves) have only the advantage of simplicity
+of operation. Nevertheless, this arrangement
+is still to be found in certain oil and benzine engines,
+notably in automobile-motors. In these motors it is
+necessary to atomize the liquid fuel by means of aspired
+air, in order to produce an explosive, gaseous mixture.</p>
+
+<p><b>Ignition.&mdash;</b>In the development of the gas-engine, the
+incandescent tube and the electric spark have taken the
+place of the obsolete naked flame. The last-mentioned
+mode of exploding the gaseous mixture will not, therefore,
+be discussed.</p>
+
+<p>The hot tube of porcelain or of metal has the indisputable
+merit of regularity of operation. The methods
+by which this operation is made as perfect as
+possible are many. Since certainty of ignition is obtained
+by means of the tube, it is important to time the
+ignition, so that it shall occur exactly at the moment
+<!--028.png--><span class='pagenum'><a name="Page_28" id="Page_28">[28]</a></span>
+when the piston is at the dead center. It has been
+previously stated that premature or belated ignition of
+the explosive mixture appreciably lessens the amount
+of useful work performed by the expansion of the gas.
+If ignition occur too soon, the mixture will be exploded
+before the piston has reached the dead center on its
+return stroke. As a result, the piston must overcome a
+considerable resistance due to the premature explosion
+and the consequent pressure. Furthermore, by reason
+of the high temperature of explosion, the gaseous products
+are very rapidly cooled. This rapid cooling causes
+a sudden drop in the pressure; and since a certain interval
+elapses between the moment of explosion and the
+moment when the piston starts on its forward stroke,
+the useful motive effort is the more diminished as the
+ignition is more premature.</p>
+
+<p><b>Incandescent Tubes.&mdash;</b>In Figs. 9 and 10 two systems
+most commonly used are illustrated. In these two arrangements,
+in which no valve is used, the length or
+height to which the tube is heated by the outer flame is
+so controlled that the gaseous mixture, which has been
+driven into the tube after compression, reaches the
+incandescent zone as nearly as possible at the exact
+moment when ignition and explosion should take place.
+The temperature of the flame of the burner, the richness
+of the gaseous mixture, and other circumstances,
+however, have a marked influence on the time of ignition,
+so that the mixture is never fired at the exact
+moment mentioned.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_009.jpg" width="600" height="472" alt="Figs. 9-10." title="" />
+<span class="caption"><span class='smcap'>Figs. 9-10.</span>&mdash;Valveless hot tubes.</span>
+</div>
+
+<p>These considerations lead to the conclusion that
+<!--029.png--><span class='pagenum'><a name="Page_29" id="Page_29">[29]</a></span>
+motors in which the mixture is exploded by hot tubes
+provided with an ignition-valve are preferable to valveless
+tubes. By the use of a special valve, positively
+controlled by the motor itself, the chances of untimely
+ignition are lessened, because it is necessary simply to
+regulate the temperature and the position of the tube
+in order that ignition may be surely effected immediately
+upon the opening of the valve, at the very moment
+the cylinder gases come into contact with the incandescent
+portion of the tube (Fig. 11). Many manufacturers,
+however, do not employ the ignition-valve on
+motors of less than 15 to 20 horse-power, chiefly because
+of the cheaper construction. The total consumption
+<!--030.png--><span class='pagenum'><a name="Page_30" id="Page_30">[30]</a></span>
+is of less moment in a motor of small than of great
+power, and the loss due to the lack of an ignition-valve
+not so marked. In a high-power engine, premature explosion
+may be the cause of the breaking of a vital
+part, such as the piston-rod or the crank-shaft. For
+this reason, a valve is indispensable for engines of more
+than 20 to 25 horse-power. A breakage of this kind is
+less to be feared in a small motor, where the parts are
+comparatively stout. The gas consumption of a well-designed
+burner does not exceed from 3.5 to 5 cubic
+feet per hour.</p>
+
+<div class="figcenter" style="width: 355px;">
+<img src="images/fig_011.jpg" width="355" height="600" alt="Fig. 11." title="" />
+<span class="caption"><span class='smcap'>Fig. 11.</span>&mdash;Ignition-tube with valve.</span>
+</div>
+
+<p><b>Electric Ignition.&mdash;</b>Electric ignition consists in producing
+a spark in the explosion-chamber of the engine.
+The nicety with which it can be controlled gives it an
+undeniable advantage over the hot tube. But the objection
+<!--031.png--><span class='pagenum'><a name="Page_31" id="Page_31">[31]</a></span>
+has been raised, perhaps with some force, that
+it entails certain complications in installing the engine.
+Its opponents even assert that the power and the rapidity
+of the deflagration of the explosive mixture are
+greater with hot-tube ignition. This reason may have
+caused the hot-tube system to prevail in England,
+where manufacturers of gas-engines are very numerous
+and not lacking in experience.</p>
+
+<p>Electric ignition is effected in gas-engines by means
+of a battery and spark-coil, or by means of a small magneto
+machine which mechanically produces a current-breaking
+spark.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_012.jpg" width="600" height="308" alt="Fig. 12." title="" />
+<span class="caption"><span class='smcap'>Fig. 12.</span>&mdash;Electric ignition by spark-coil
+and battery.</span>
+</div>
+
+<div class="figcenter" style="width: 431px;">
+<img src="images/fig_013.jpg" width="431" height="500" alt="Fig. 13." title="" />
+<span class="caption"><span class='smcap'>Fig. 13.</span>&mdash;Spark-plug.</span>
+</div>
+
+<p><b>Electric Ignition by Battery and Induction-Coil.&mdash;</b>The
+first system is the cheaper; but it exacts the most
+painstaking care in maintaining the parts in proper
+working condition. It comprises three essential elements&mdash;a
+battery, a coil, and a spark-plug (Fig. 12).
+The battery may be a storage-battery, which must, consequently,
+be recharged from time to time; or it may be
+<!--032.png--><span class='pagenum'><a name="Page_32" id="Page_32">[32]</a></span>
+a primary battery which must be frequently renewed
+and carefully cleaned. The induction-coil is fitted with
+a trembler or interrupter, which easily gets out of order
+and which must be regulated with considerable accuracy.
+The spark-plug is a particularly delicate part,
+subject to many possible accidents. The porcelain of
+which it is made is liable to crack. It is hard to obtain
+absolutely perfect insulation; for the terminals deteriorate
+as they become overheated, break, or become foul
+(Fig. 13). In oil-engines, especially, soot is rapidly
+deposited on the terminals, so that no spark can be produced.
+In benzine or naphtha motors, such an accident
+is less likely to happen. In automobile-motors, however,
+the spark-plug only too often fails to perform its
+function. The one remedy for these evils is to be found
+<!--033.png--><span class='pagenum'><a name="Page_33" id="Page_33">[33]</a></span>
+in the most painstaking care of the spark-plug and of
+the other elements of the ignition system.</p>
+
+<div class="figcenter" style="width: 488px;">
+<img src="images/fig_014.jpg" width="488" height="600" alt="Fig. 14." title="" />
+<span class="caption"><span class='smcap'>Fig. 14.</span>&mdash;Magneto ignition apparatus.</span>
+</div>
+
+<div class="figcenter" style="width: 575px;">
+<img src="images/fig_015.jpg" width="575" height="600" alt="Fig. 15." title="" />
+<span class="caption"><span class='smcap'>Fig. 15.</span>&mdash;General view and details of a magneto
+ignition apparatus.</span>
+</div>
+
+<p><b>Ignition by Magnetos.&mdash;</b>Magneto apparatus, on the
+other hand, are noteworthy for the regularity of their
+operation. They may be used for several years without
+being remagnetized, and require no exceptional
+care. Magneto ignition devices are mechanically actuated,
+the necessary displacement of the coil being
+effected by means of a cam carried on a shaft turning
+with half the motor speed (Figs. 14 and 15). At the
+moment when it is released by the cam, the coil is suddenly
+<!--034.png--><span class='pagenum'><a name="Page_34" id="Page_34">[34]</a></span>
+returned to its initial position by means of a
+spring. This rapid movement generates a current that
+passes through terminals, which are arranged within
+the cylinder and which are immediately separated by
+mechanical means. Thus a much hotter circuit-breaking
+spark is produced, which is very much more
+energetic than that of a battery and induction-coil, and
+which surely ignites the gaseous mixture in the cylinder.
+The terminals are generally of steel, sometimes
+pointed with nickel or platinum (Fig. 16). The only
+precaution to be observed is the exclusion of moisture
+<!--035.png--><span class='pagenum'><a name="Page_35" id="Page_35">[35]</a></span>
+and occasional cleaning. For engines driven by producer-gas
+magneto-igniters are preferable to cells and
+batteries. In general, electrical ignition is to be recommended
+for high-pressure engines.</p>
+
+<div class="figcenter" style="width: 483px;">
+<img src="images/fig_016.jpg" width="483" height="500" alt="Fig. 16." title="" />
+<span class="caption"><span class='smcap'>Fig. 16.</span>&mdash;Contacts of a magneto-igniter.</span>
+</div>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_017.jpg" width="600" height="593" alt="Fig. 17." title="" />
+<span class="caption"><span class='smcap'>Fig. 17.</span>&mdash;Device for regulating the moment of
+ignition.</span>
+</div>
+
+<p>In order to explain more clearly modern methods of
+ignition a diagram is presented, showing an electric
+magneto-igniter applied to the cylinder-head of a
+Winterthur motor, and also a sectional view of the
+member varying the make-and-break contacts which
+<!--036.png--><span class='pagenum'>36</span>
+are mounted in the explosion-chamber (Figs. 18 and
+19)</p>
+
+<p>1. The magneto <i>A</i> consists of horseshoe-magnets,
+between the poles of which the armature rotates. At
+its conically turned end, the armature-shaft carries an
+arm <i>B</i>, held in place by a nut.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_018.jpg" width="600" height="582" alt="Fig. 18." title="" />
+<span class="caption"><span class='smcap'>Fig. 18.</span>&mdash;Winterthur electric ignition system.</span>
+</div>
+
+<p>2. The igniter <i>C</i> is a casting secured to the cylinder-head
+by a movable strap and provided with two axes
+<i>D</i> and <i>M</i>, of which the one, <i>D</i>, made of bronze, is
+movable, and is fitted with a small interior contact-hammer,
+a percussion-lever, and an exterior recoil-spring;
+the other, <i>M</i>, is fixed, insulated, and arranged
+<!--037.png--><span class='pagenum'><a name="Page_37" id="Page_37">[37]</a></span>
+to receive the current from the magneto <i>A</i>, by means
+of an insulated copper wire <i>E</i>.</p>
+
+<p>3. The spring <i>F</i> comprises two continuous coils contained
+in a brass casing, and actuating a steel striking
+or percussion-pin.</p>
+
+<p>4. The controlling devices of the magneto include a
+stem or rod <i>G</i>, slidable in a guide <i>H</i>, provided with a
+safety spring and mounted on an eccentric spindle, the
+position of which can be varied by means of a regulating-lever
+(<i>I</i>). The rod is operated from the distributing-shaft,
+on the conical end of which a cam <i>J</i>
+carrying a spindle is secured.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_019.jpg" width="600" height="515" alt="Fig. 19." title="" />
+<span class="caption"><span class='smcap'>Fig. 19.</span>&mdash;Contacts of the Winterthur system.</span>
+</div>
+
+<p><i>Regulation of the Magneto.&mdash;</i>The position assumed
+by the armature when at rest is a matter of importance
+in obtaining a good spark on breaking the circuit. The
+marks on the armature should be noted. The position
+<!--038.png--><span class='pagenum'>38</span>
+of the armature may be experimentally varied, in order
+to obtain a spark of maximum intensity, by changing
+the position of the arm B on the armature-shaft.</p>
+
+<p><i>Control of the Magneto.&mdash;</i>The controlling gear
+should enable the armature to oscillate from 20 to 25
+degrees. The time at which the breaking of the circuit
+is effected can be regulated by shifting the handle (<i>I</i>).
+In starting the engine, the circuit can be broken with
+a slight retardation, which is lessened as the engine
+attains its normal speed.</p>
+
+<p><i>Igniter.&mdash;</i>It is advisable that there should be a play
+of <sup>1</sup>&frasl;<sub>2</sub> mm. (0.0196 in.) between the lever <i>Z</i> when at
+rest and the striking-pin. The axis <i>D</i> of the circuit-breaking
+device should be easily movable; and the
+hammer which it carries at its end toward the interior
+of the cylinder should be in perfect contact with the
+stationary spindle <i>M</i>, which is electrically insulated.
+This spindle <i>M</i> should be well enclosed, in order to
+prevent any leakage that might cause a deterioration of
+the insulating material.</p>
+
+<p>The subject of ignition is of such extreme importance
+that the author will recur to it from time to time
+in the various chapters of this book. Too much stress
+cannot be laid upon proper timing; otherwise there
+will be a needless waste of power. Cleanliness is a
+point that must be observed scrupulously; for spark-plugs
+are apt to foul only too readily, with the result
+that short-circuits and misfires are apt to occur. In
+oil and volatile hydrocarbon engines the tendency to
+fouling is particularly noticeable. In the chapter devoted
+<!--039.png--><span class='pagenum'><a name="Page_39" id="Page_39">[39]</a></span>
+to these forms of motors the author has dwelt
+upon the precautions that should be taken to forestall a
+possible derangement of the ignition apparatus. As a
+general rule the ignition apparatus installed by trustworthy
+manufacturers will be found best suited for the
+requirements of the engine.</p>
+
+<p>The apparatus should be fitted with a device by
+which the ignition can be duly timed by hand during
+operation (Fig. 17).</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_020.jpg" width="600" height="590" alt="Fig. 20." title="" />
+<span class="caption"><span class='smcap'>Fig. 20.</span>&mdash;Design of the piston.</span>
+</div>
+
+<p><b>The Piston.&mdash;</b>Coming, as it does, continually in contact
+with the ignited gases, the piston is gradually
+heated to a high temperature. The rear face of the
+piston should preferably be plane. Curved surfaces
+are not to be recommended because they cool off
+badly. Likewise, faces having either inserted parts
+or bolt-heads are to be avoided, since they are liable to
+become red-hot and to ignite the mixture prematurely
+(Fig. 20).
+<!--040.png--><span class='pagenum'><a name="Page_40" id="Page_40">[40]</a></span></p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_021.jpg" width="600" height="281" alt="Fig. 21." title="" />
+<span class="caption"><span class='smcap'>Fig. 21.</span>&mdash;Piston with lubricated pin.</span>
+</div>
+
+<p>Among the parts of the piston which rapidly wear
+away because constant lubrication is difficult, is the
+connection with the piston-rod (Fig. 21). It is important
+that the bearing at the piston-pin be formed of
+two parts which can be adjusted to take up the wear.
+The pin itself should be of case-hardened steel. For
+large engines, some manufacturers have apparently
+abandoned the practice of locking the pin, by set-screws,
+in flanges cast in one piece with the piston. Indeed,
+the piston is often fractured by reason of the expansion
+of the pins thus held on two sides. It seems advisable
+to secure the pin by means of a single screw in one of
+the flanges, fitting it by pressure against the opposite
+boss. The use of wedges or of clamping-screws, introduced
+from without the piston to hold the pin,
+should be avoided. It may happen that the wedges
+will be loosened, will move out, and will grind the
+cylinder, causing injuries that cannot be detected before
+it is too late. The strength of the piston-pin should be
+so calculated that the pressure per square inch of projected
+surface does not exceed 1,500 to 2,850 pounds
+per square inch. It should be borne in mind that the
+<!--041.png--><span class='pagenum'><a name="Page_41" id="Page_41">[41]</a></span>
+initial pressure of the explosion is often equal to 400 to
+425 pounds per square inch. Some manufacturers
+mount the pin as far to the back of the piston as possible,
+so as to bring it nearer the point of application of
+the motive force of the explosion. Other manufacturers,
+on the other hand, mount the pin toward the
+front of the piston. No great objection can be raised
+against either method. In the former case the position
+of the rings will limit that of the pin.</p>
+
+<p>The number of these rings ought not to be less than
+four or five, arranged at the rear of the piston. It is
+to be observed that makers of good engines use as many
+as 8 to 10 rings in the pistons of fair-sized motors.</p>
+
+<p>Piston-rings of gray pig-iron can be adjusted with
+the greatest nicety in such a manner that, by means
+of tongues fitting in their grooves, they are held from
+turning in the latter, whereby their openings are prevented
+from registering and allowing the passage of
+gas. As a general rule, a large number of rings
+may be considered a distinguishing feature of a well-built
+engine. In order to prevent a too rapid wear of
+the cylinder, several German manufacturers finish off
+the front of the piston with bronze or anti-friction
+metal in engines of more than 40 to 50 horse-power. It
+is to be observed, however, that this expedient is not
+applicable to motors the cylinders of which are comparatively
+cold; otherwise the bronze or anti-friction
+metal will deteriorate.</p>
+
+<p><b>Arrangement of the Cylinder.&mdash;</b>The cylinder shell
+or liner, in which the piston travels, and the water-jacket
+<!--042.png--><span class='pagenum'><a name="Page_42" id="Page_42">[42]</a></span>
+should preferably be made in separate pieces and
+not cast of the same metal, in order to permit a free
+expansion (Figs. 22 and 23). If for want of care or
+of proper lubrication, which frequently occurs in gas-engines,
+the cylinder should be injured by grinding,
+it can be easily renewed, without the loss of all the connecting
+parts.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_022.jpg" width="600" height="299" alt="Fig. 22." title="" />
+<span class="caption"><span class='smcap'>Fig. 22.</span>&mdash;Head, jacket and liner of cylinder, cast
+in one piece.</span>
+</div>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_023.jpg" width="600" height="416" alt="Fig. 23." title="" />
+<span class="caption"><span class='smcap'>Fig. 23.</span>&mdash;Cylinder with independent liner and
+head.</span>
+</div>
+
+<p>For the same reason, the cylinder and its casing
+should be independent of the frame. In many horizontal
+engines, the cylinders overhang the frame throughout
+the entire length, by reason of the joining of their
+<!--043.png--><span class='pagenum'><a name="Page_43" id="Page_43">[43]</a></span>
+front portions with the frames. Although such a construction
+is attended with no serious consequences in
+small engines, nevertheless in large engines it is exceedingly
+harmful. Indeed, in most modern single-acting
+engines, the pistons are directly connected with
+the crank-shaft by the piston-rod, without any intermediate
+connecting-rod or cross-head. The vertical reaction
+of the motive effort on the piston is, therefore,
+taken up entirely by the thrust of the cylinder, which
+is also vertical (Fig. 24). This thrust, acting against
+an unsupported part, may cause fractures; at any rate,
+it entails a rapid deterioration of the cylinder joint.</p>
+
+<div class="figcenter" style="width: 513px;">
+<img src="images/fig_024.jpg" width="513" height="600" alt="Fig. 24." title="" />
+<span class="caption"><span class='smcap'>Fig. 24.</span>&mdash;Single-acting engines.</span>
+</div>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_025.jpg" width="600" height="362" alt="Fig. 25." title="" />
+<span class="caption"><span class='smcap'>Fig. 25.</span>&mdash;Engine with inclined bearings.</span>
+</div>
+
+<p><b>The Frame.&mdash;</b>Gas-engines driven as they are, by explosions,
+giving rise to shocks and blows, should be
+built with frames, heavy, substantial, and broad-based,
+<!--044.png--><span class='pagenum'><a name="Page_44" id="Page_44">[44]</a></span>
+so as to rest solidly on the ground. This essential condition
+is often fulfilled at the cost of the engine's appearance;
+but appearance will be willingly sacrificed
+to meet one of the requirements of perfect operation.
+For engines of more than 8 to 10 horse-power, frames
+should be employed which can be secured to the
+masonry foundation without a separate pedestal or base.
+Some manufacturers, for the purpose of lightening the
+frame, attach but little importance to the foundation
+and to strength of construction, and employ the design
+illustrated in place of the crank-shaft bearing (Fig.
+25); others, in order to facilitate the adjusting of the
+connecting-rod bearings, prefer the second form (Fig.
+26). It is evident that, in the first case, a part of the
+effort produced by the explosion reacts on the upper
+portion of the connecting-rod bearing, on the cap of
+the crank-shaft bearing, and consequently on the fastening-bolts.
+In the second case, if the adjustment
+be not very carefully made, or if the rubbing surfaces
+are insufficient, the entire thrust due to the explosion
+<!--045.png--><span class='pagenum'><a name="Page_45" id="Page_45">[45]</a></span>
+will be received by the meeting parts of the two bushings,
+thus injuring them and causing a more rapid
+wear. In the construction of large engines, some manufacturers
+take the precaution of forming the connecting-rod
+bearings of four parts, adjustable to take up the
+wear, so that the effort is exerted against the parts disposed
+at right angles to each other. A form that seems
+rational is that shown in Fig. 27, in which the reaction
+of the thrust is taken up by the lower bearing, rigidly
+supported by the braced frame, in the direction opposite
+to that of the explosive effort.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_026.jpg" width="600" height="390" alt="Fig. 26." title="" />
+<span class="caption"><span class='smcap'>Fig. 26.</span>&mdash;Engine with straight bearings.</span>
+</div>
+
+<!--046.png--><div class="figcenter" style="width: 600px;">
+<img src="images/fig_027.jpg" width="600" height="308" alt="Fig. 27." title="" />
+<span class="caption"><span class='smcap'>Fig. 27.</span>&mdash;Engine with correctly designed
+bearings.</span>
+</div><p><span class='pagenum'><a name="Page_46" id="Page_46">[46]</a></span></p>
+
+<p>The sum of the projecting surfaces of the two bearings
+should be so calculated that a maximum explosive
+pressure of 405 to 425 pounds per square inch will not
+subject the bearings to a pressure higher than 425 to
+550 pounds per square inch.</p>
+
+<p><b>Fly-Wheels.&mdash;</b>In gas-engines particularly, the fly-wheel
+should be secured to the crank-shaft with the utmost
+care. It should be mounted as near as possible
+to the bearings; otherwise the alinement of the shaft
+will be destroyed and its strength impaired. If the fly-wheel
+be fastened by means of a key or wedge having
+a projecting head, it is advisable to cover the end of the
+shaft by a movable sleeve. The fly-wheel should run
+absolutely true and straight even if the explosion be
+premature. In well-built engines the fly-wheels are
+lined up and shaped to the rim. The periphery is
+slightly rounded in order the better to guide the belt
+when applied to the wheel.</p>
+
+<!--047.png--><p><span class='pagenum'>47</span></p>
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_028.jpg" width="600" height="254" alt="Fig. 28." title="" />
+<span class="caption"><span class='smcap'>Fig. 28.</span>&mdash;Single fly-wheel engine with external
+bearing.</span>
+</div>
+
+<p>Furthermore, fly-wheels should be nicely balanced;
+those are to be preferred which have no counter-weights
+cast or fastened to the hub, the spokes, or the rim.
+The system of balancing the engine by means of two
+fly-wheels, mounted on opposite sides, is used chiefly
+for the purpose of equalizing the inertia effects. Special
+engines, employed for driving dynamos, and even
+industrial engines of high power, are preferably fitted
+with but a single fly-wheel, with an outer bearing, since
+they more readily counteract the cyclic irregularities or
+variations of speed occurring in a single revolution
+(Fig. 28). If in this case a pulley be provided, it
+<!--048.png--><span class='pagenum'><a name="Page_48" id="Page_48">[48]</a></span>
+should be mounted between the engine and the outer
+bearing. The following advantages may be cited in
+favor of the single fly-wheel, particularly in the case of
+dynamo-driving engines:</p>
+
+<p>1. The single fly-wheel permits a more ready access
+to the parts to be examined.</p>
+
+<p>2. It involves the employment of a third bearing,
+thus avoiding the overhang caused by two ordinary fly-wheels.</p>
+
+<p>3. It avoids the torsional strain to which the two-wheel
+crank is subjected when starting, stopping, and
+changing the load, the peripheral resistance varying
+in one of the fly-wheels, while the other is subjected to
+a strain in the opposite direction on account of the
+inertia.</p>
+
+<p>4. Two fly-wheels, keyed as they are to projecting
+ends of the shaft, will be so affected at the rims by the
+explosions that the belts will shake.</p>
+
+<p>The third bearing which characterizes the single-fly-wheel
+system, is but an independent support, resting
+solidly on the masonry bed of the engine. The
+bearing with its independent support is sufficiently
+rigid, and is not subjected to any stress from the crank
+at the moment of explosion, the reaction of the crank
+affecting only the frame bearings. With such fly-wheels,
+reputable firms guarantee a cyclic regularity
+which compares favorably with that of the best steam-engines.
+For a duty varying from a third of the load to
+the maximum load, these engines, when driving direct-current
+dynamos for directly supplying an electric-light
+<!--049.png--><span class='pagenum'><a name="Page_49" id="Page_49">[49]</a></span>
+circuit, will insure perfect steadiness of the light;
+and the effectually aperiodic measuring instruments
+will not indicate fluctuations greater than 2 to 3 per
+cent. of the tension or intensity of the current. The
+coefficient of the variations in the speed of a single revolution
+will thus be not far from <sup>1</sup>&frasl;<sub>60</sub>.</p>
+
+<div class="figcenter" style="width: 400px;">
+<img src="images/fig_029.jpg" width="400" height="385" alt="Fig. 29." title="" />
+<span class="caption"><span class='smcap'>Fig. 29.</span>&mdash;Curved spoke fly-wheel.</span>
+</div>
+
+<p><b>Straight and Curved Spoke Fly-Wheels.&mdash;</b>The
+spokes of fly-wheels are either straight or curved. In
+assembling the motor parts it too often occurs that
+curved spoke fly-wheels are mounted with utter disregard
+of the direction in which they are to turn. It
+is important that curved spokes should be subjected to
+compression and not to traction. Hence the fly-wheels
+<!--050.png--><span class='pagenum'><a name="Page_50" id="Page_50">[50]</a></span>
+should be so mounted that the concave portions of the
+spokes travel in the direction of rotation, as shown in
+the accompanying diagram (Fig. 29). If a single fly-wheel
+be employed on an engine of the type in which
+the speed is governed by the "hit-and-miss" system,
+the fly-wheel should be extra heavy to counteract the irregularities
+of the motive impulses when the engine is
+not working at its full load, or in other words, when no
+explosion takes place at every cycle.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_030.jpg" width="600" height="208" alt="Fig. 30." title="" />
+<span class="caption"><span class='smcap'>Fig. 30.</span>&mdash;Forged crank-shafts.</span>
+</div>
+
+<p><b>The Crank-Shaft.&mdash;</b>The crank-shaft should be made
+of the best mild steel. Those shafts are to be preferred
+the cranks of which are not forged on (Fig. 30), but
+cut out of the mass of metal; furthermore, the brackets
+or supports should be planed and shaped so that they
+are square in cross-section.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_031.jpg" width="600" height="236" alt="Fig. 31." title="" />
+<span class="caption"><span class='smcap'>Fig. 31.</span>&mdash;Correct design of crank-shaft.</span>
+</div>
+<!--051.png--><p><span class='pagenum'><a name="Page_51" id="Page_51">[51]</a></span></p>
+
+<p>Such a design involves fine workmanship and speaks
+well for the construction of the whole engine. Moreover,
+it enables the bearings to be brought nearer each
+other, reduces to a minimum that part of the crank-shaft
+which may be considered the weakest, and permits
+a rational and exact counterbalancing of the moving
+parts, such as the crank and the end of the connecting-rod.
+The best manufacturers have adopted the
+method of fastening to the cranks balancing weights
+secured to the brackets, especially for high-speed engines
+or for engines of high power. The projecting
+surface of the crank-pin should, as a rule, be calculated
+for a pressure of 1,400 pounds per square inch.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_032.jpg" width="600" height="245" alt="Fig. 32." title="" />
+<span class="caption"><span class='smcap'>Fig. 32.</span>&mdash;Crank-shaft with balancing weight.</span>
+</div>
+
+<p><b>Cams, Rollers, etc.&mdash;</b>The cams, rollers, thrust-bearings,
+as well as the piston-pin in particular, should be
+made of good steel, case-hardened to a depth of at least
+.08 of an inch. Their hardness and the degree of
+cementation may be tested by means of a file. This is
+the method followed by the best manufacturers.</p>
+
+<p><b>Bearings.&mdash;</b>All the bearings and all guides should
+be adjustable to take up the wear. They are usually
+made of bronze or of the best anti-friction metal.
+<!--052.png--><span class='pagenum'><a name="Page_52" id="Page_52">[52]</a></span></p>
+
+<p><b>Steadiness.&mdash;</b>The steadiness of engines may be considered
+from two different standpoints.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_033.jpg" width="600" height="336" alt="Fig. 33." title="" />
+<span class="caption"><span class='smcap'>Fig. 33.</span>&mdash;Inertia governor.</span>
+</div>
+
+<p>1. <i>Variation of the Number of Revolutions at Different
+Loads.&mdash;</i>This depends chiefly on the sensitiveness
+of the governor, which should be of the "inertia"
+or of the "ball" (or centrifugal) type. The first form
+is rarely employed, except in small engines up to 10
+horse-power, and is applicable only to engines in which
+the "hit and miss" system is employed (Fig. 33). The
+second form is more widely used, and is applicable to
+engines having "hit-and-miss" or variable admission
+devices. In the first form, the governor simply displaces
+a very light member, whatever may be the size of the
+engine, for which reason the dimensions are very small.
+In the second form, on the other hand, the governor
+acts either on a conical sleeve or on some other regulating
+member offering resistance. Evidently, in order to
+<!--053.png--><span class='pagenum'><a name="Page_53" id="Page_53">[53]</a></span>
+overcome the reactions to which it is subjected, it must
+be as heavy and powerful as a steam-engine governor.
+Sufficient allowance is made in a good engine for
+variation in the number of revolutions between no load
+and full load, not greater than two per cent. if the
+admission be of the "hit-and-miss" type, and five per
+cent. if it be of the variable type.</p>
+
+<p>2. <i>Cyclic Regularity.&mdash;</i>This term means simply that
+the speed of the engine is constant in a single revolution.
+In practice this is never attained. Allowance is
+made in engines used for driving direct-current dynamos
+for a variation of about <sup>1</sup>&frasl;<sub>60</sub>; while in industrial
+engines a variation of <sup>1</sup>&frasl;<sub>25</sub> is permissible. Cyclic variation
+depends only on the weight of the fly-wheel;
+whereas variation in the number of revolutions is determined
+chiefly by the governor.</p>
+
+<p><b>Governors.&mdash;</b>Diagrams are here presented of the
+principal types of governors&mdash;the inertia governor, the
+ball or centrifugal governor controlling an admission-valve
+of the "hit-and-miss" type (Fig. 34), and the
+ball or centrifugal governor controlling a variable gas-admission
+valve (Fig. 35).</p>
+
+<p>In distinguishing between the operation of the two
+last-mentioned types, it may be stated that the former
+bears the same relation to the hit-and-miss gear as it
+does, for example, to the valve gear of a Corliss steam-engine.
+In other words, it is an apparatus that <i>indicates</i>
+without <i>inducing</i>, admission or cut-off. The second
+type, on the other hand, operates by means of slides
+and the like, as in the Ridder type of engine, in which
+<!--054.png--><span class='pagenum'><a name="Page_54" id="Page_54">[54]</a></span>
+it controls the displacement of the cut-off or distribution
+slide-valve and is subjected to variable forces, depending
+on the pressure, lubrication, the condition of
+the stuffing-boxes, and the like.</p>
+
+<p>In gas as well as in steam engines, designs are to be
+commended which shield the delicate mechanism from
+strains and stresses that are likely to destroy its sensitiveness,
+as is the case in the automatic cut-off of the
+Corliss steam-engine.</p>
+
+<div class="figcenter" style="width: 532px;">
+<img src="images/fig_034.jpg" width="532" height="600" alt="Fig. 34." title="" />
+<span class="caption"><span class='smcap'>Fig. 34.</span>&mdash;&quot;Hit-and-miss&quot; governor.</span>
+</div>
+
+<p>Governors should be provided with means to permit
+the manual variation of the speed while the engine is in
+operation.</p>
+
+<p>For small motors, one of the most widely used admission
+devices is that of the "hit-and-miss" type. As
+its name indicates, this admission arrangement allows
+<!--055.png--><span class='pagenum'><a name="Page_55" id="Page_55">[55]</a></span>
+a given quantity of gas to enter the cylinder for a number
+of consecutive intervals, until the engine is about
+to exceed its normal speed. Thereupon the governor
+cuts off the gas entirely. The result is that, in this
+system, the number of admissions is variable, but that
+each admitted charge is composed of a constant proportion
+of gas and air.</p>
+
+<p>The governors employed for the "hit-and-miss"
+type are either "inertia" or "centrifugal" governors.</p>
+
+<p>Inertia governors (Fig. 33) are less sensitive than
+those of the centrifugal type. They are generally applied
+only to industrial engines of small power, in
+which regularity of operation is a secondary consideration.</p>
+
+<p>Centrifugal governors employed for gas-engines
+with "hit-and-miss" regulation are, as a general rule,
+noteworthy for their small size, which is accounted for
+by the fact that, in most systems, merely a movable
+member is placed between the admission-controlling
+means and the valve-stem (Fig. 34). It follows that
+this method of operation relieves the governor of the
+necessity of overcoming the resistance of the weight of
+moving parts, more or less effectually lubricated, and
+subjected to the reaction of the parts which they control.</p>
+
+<p>In engines equipped with variable admission devices
+for the gas or the explosive mixture, the governor actuates
+a sleeve on which the admission-cam is fastened
+(Fig. 35). Or, the governor may displace a conical
+cam, the reaction of which, on contact with the lever,
+<!--056.png--><span class='pagenum'><a name="Page_56" id="Page_56">[56]</a></span>
+destroys the stability of the governor. These conditions
+justify the employment of powerful governors
+which, on account of the inertia of their parts, diminish
+the reactionary forces encountered.</p>
+
+<p>The centrifugal governor should be sufficiently effectual
+to prevent variations in the number of revolutions
+within the limits of 2 to 3 per cent. between no
+load and approximately full load. Under equivalent
+conditions, the inertia governor can hardly be relied
+upon for a coefficient of regularity greater than 4 to
+5 per cent.</p>
+
+<div class="figcenter" style="width: 548px;">
+<img src="images/fig_035.jpg" width="548" height="600" alt="Fig. 35." title="" />
+<span class="caption"><span class='smcap'>Fig. 35.</span>&mdash;Variable admission governor.</span>
+</div>
+
+<p>The manner of a governor's operation is necessarily
+dependent on the admission system adopted. And the
+admission system varies essentially with the size, the
+purpose of the engine, and the character of the fuel employed.</p>
+
+<div class="figcenter" style="width: 395px;">
+<img src="images/fig_036.jpg" width="395" height="600" alt="Fig. 36." title="" />
+<span class="caption"><span class='smcap'>Fig. 36.</span>&mdash;Vertical engine.</span>
+</div>
+
+<div class="figcenter" style="width: 407px;">
+<img src="images/fig_037.jpg" width="407" height="600" alt="Fig. 37." title="" />
+<span class="caption"><span class='smcap'>Fig. 37.</span>&mdash;Section through an engine of the vertical
+or &quot;steam-hammer&quot; type.</span>
+</div>
+
+<p><b>Vertical Engines.&mdash;</b>For some years past there seems
+to have been a tendency in Europe to use horizontal
+instead of vertical engines, especially since engines of
+<!--057.png--><span class='pagenum'><a name="Page_57" id="Page_57">[57]</a></span>
+more than 10 or 15 horse-power have been extensively
+used for industrial purposes. The vertical type is used
+for 1 to 8 horse-power engines, with the cylinder in the
+lower part of the frame, and the shaft and its fly-wheel
+in the upper part (Fig. 36). The only merit to be
+attributed to this arrangement is a great saving of space.
+It is evident, however, that beyond a certain size and
+power, such engines are unstable. In America particularly,
+many manufacturers of high-power engines (50
+to 100 horse-power or more) prefer the vertical or
+"steam-hammer" arrangement, which consists in placing
+the cylinder in the upper part, and the shaft in the
+lower part of the frame as close to the ground as possible
+(Figs. 37 and 38). The problem of saving space, as
+well as that of insuring stability, is thus solved, so that
+it is easily possible to run up the speed of the engine.
+There is also the advantage that the shaft of a dynamo
+<!--059.png--><span class='pagenum'>59</span>
+can be directly coupled up with the crank-shaft of the
+engine, thus dispensing with a belt, which, at the least,
+absorbs 4 to 6 per cent. of the total power. It should,
+nevertheless, be borne in mind that the direct coupling
+<!--060.png--><span class='pagenum'><a name="Page_60" id="Page_60">[60]</a></span>
+of electric generators to engine-shafts implies the use
+of extremely large and, therefore, of extremely costly
+dynamos. Furthermore, by reason of this arrangement,
+groups of electro-generators can be disposed in a comparatively
+small amount of space. Some English manufacturers
+are also beginning to adopt the "steam-hammer"
+type of engine for high powers, the result
+being a marked saving in material and lowering of the
+cost of installation.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_038.jpg" width="600" height="303" alt="Fig. 38." title="" />
+<span class="caption"><span class='smcap'>Fig. 38.</span>&mdash;Side and end elevations of a vertical
+or &quot;steam-hammer&quot; engine.</span>
+</div>
+
+<p><b>Power of the Engine.&mdash;</b>The first thing to be considered
+is that the power of a gas-engine is always given
+in "effective" horse-power, and that the power of a
+steam-engine is always given in "indicated" horse-power
+in contracts of sale. In England and in the
+United States, the expression "nominal" horse-power
+is still employed. It may be advisable to define these
+various terms exactly, since unscrupulous dealers, to
+the buyer's loss, have done much to confuse them.</p>
+
+<p>"Indicated" horse-power is a designation applied to
+the theoretical power produced by the action of the
+motive agent on the piston. The work performed is
+measured on an indicator card, by means of which the
+average pressure to be considered in the computation of
+the theoretical power is ascertained.</p>
+
+<p>The "effective" or brake horse-power is equal to the
+"indicated" horse-power, less the energy absorbed by
+passive resistance, friction of the moving parts, etc.</p>
+
+<p>The "effective" work is an experimental term applied
+to the power actually developed at the shaft.
+This work is of interest solely to the engine user.
+<!--061.png--><span class='pagenum'><a name="Page_61" id="Page_61">[61]</a></span></p>
+
+<p>In a well-built motor, in which the passive resistance
+by reason of the correct adjustment and simplicity of
+the parts, is reduced to a minimum, the "effective"
+horse-power is about 80 to 87 per cent. of the "indicated"
+horse-power, when the engine runs under full
+load. This reduced output is usually called the
+"mechanical efficiency" of the engine.</p>
+
+<p>"Nominal" horse-power is an arbitrary term in the
+sense in which it is used in England and America,
+where it is quite common. The manufacturers themselves
+do not seem to agree on its absolute value. A
+"nominal" horse-power, however, is equal to anything
+from 3 to 4 "effective" horse-power. The uncertainty
+which ensues from the use of the term should lead to
+its abandonment.</p>
+
+<p>In installing a motor, the determination of its horse-power
+is a matter of grave importance, which should
+not be considered as if the motor were a steam-engine
+or an engine of some other type. It must not be forgotten
+that, especially at full load, explosion-engines
+are most efficient, and that, under these conditions, it
+will generally be advisable to subordinate the utility of
+having a reserve power to the economy which follows
+from the employment of a motor running at a load
+close to its maximum capacity. On the other hand, the
+gas-engine user is unwilling to believe that the stipulated
+horse-power of the motor which is sold to him is
+the greatest that it is capable of developing under industrial
+conditions. Business competition has led some
+firms to sell their engines to meet these conditions. It
+<!--062.png--><span class='pagenum'><a name="Page_62" id="Page_62">[62]</a></span>
+is probably not stretching the truth too far to declare
+that 80 per cent. of the engines sold with no exact contract
+specifications are incapable of maintaining for
+more than a half hour the power which is attributed
+to them, and which the buyer expects. It follows that
+the power at which the engine is sold should be both
+industrially realized and maintained, if need be, for an
+entire day, without the engine's showing the slightest
+perturbation, or faltering in its silent and regular operation.
+To attain this end, it is essential that the energy
+developed by the engine in normal or constant operation
+should not exceed 90 to 95 per cent. of the maximum
+power which it is able to yield, and which may be
+termed its "utmost power". As a general rule,
+especially for installations in which the power fluctuates
+from the lowest possible to double this, as much
+attention must be paid to the consumption at half load
+as at full load; and preference should be given to the
+engine which, other things being equal, will operate
+most economically at its lowest load. In this case the
+consumption per effective horse-power is appreciably
+higher. Generally, this consumption is greater by 20
+to 30 per cent. than that at full load. This is particularly
+true of the single-acting engines so widely used
+for horse-powers less than 100 to 150.</p>
+
+<p>In some double or triple-acting engines, according
+to certain writers, the diminution in the consumption
+will hardly be proportional to the diminution of the
+power, or at any rate, the difference between the consumption
+per B.H.P. at full load and at reduced load
+<!--063.png--><span class='pagenum'><a name="Page_63" id="Page_63">[63]</a></span>
+will be less than in other engines. It should be observed,
+however, that this statement is apparently not
+borne out by experiments which the author has had
+occasion to make. To a slight degree, this economy is
+obtained at the cost of simplicity, and consequently, at
+the cost of the engine. At all events, the engines have
+the merit of great cyclic regularity, rendering them
+serviceable for driving electric-light dynamos; but this
+regularity can also be attained by the use of the extra
+heavy fly-wheels which English firms, in particular,
+have introduced.</p>
+
+<p><b>Automatic Starting.&mdash;</b>When the gas-engine was first
+introduced, starting was effected simply by manually
+turning the fly-wheel until steady running was assured.
+This procedure, altogether too crude in its way, is
+attended with some danger. In a few countries it is
+prohibited by laws regulating the employment of industrial
+machinery. If the engine be of rather large
+size one, moreover, which operates at high pressure&mdash;such
+a method of starting is very troublesome.
+For these reasons, among others, manufacturers have
+devised automatic means of setting a gas-engine in
+motion.</p>
+
+<p>Of such automatic devices, the first that shall be
+mentioned is a combination of pipes, provided with
+cocks, by the manipulation of which, a certain amount
+of gas, drawn from the supply pipe, is introduced into
+the engine-cylinder. The piston is first placed in a
+suitable position, and behind it a mixture is formed
+which is ignited by a naked flame situated near a convenient
+<!--064.png--><span class='pagenum'><a name="Page_64" id="Page_64">[64]</a></span>
+orifice. When the explosion takes place the
+ignition-orifice is automatically closed, and the piston
+is given its motive impulse. The engine thus started
+continues to run in accordance with the regular recurrence
+of the cycles. In this system, starting is effected
+by the explosion of a mixture, without previous compression.</p>
+
+<p>Some designers have devised a system of hand-pumps
+which compress in the cylinder a mixture of
+air and gas, ignited at the proper time by allowing it
+to come into contact with the igniter, through the manipulation
+of cocks (Fig. 39).</p>
+
+<p>These two methods are not absolutely effective.
+They require a certain deftness which can be acquired
+only after some practice. Furthermore, they are objectionable
+because the starting is effected too violently,
+and because the instantaneous explosion subjects the
+stationary piston, crank, and fly-wheel to a shock so
+sudden that they may be severely strained and may even
+break. Moreover, the slightest leakage in one of the
+valves or checks may cause the entire system to fail,
+and, particularly in the case of the pump, may induce
+a back explosion exceedingly dangerous to the man in
+charge of the engine.</p>
+
+<p>These systems are now almost generally supplanted
+by the compressed-air system, which is simpler, less
+dangerous, and more certain in its effect.</p>
+
+<p>The elements comprising the system in question include
+essentially a reservoir of thick sheet iron, capable
+of resisting a pressure of 180 to 225 pounds and sufficient
+<!--065.png--><span class='pagenum'><a name="Page_65" id="Page_65">[65]</a></span>
+in capacity to start an engine several times. This
+reservoir is connected with the engine by piping, which
+is disposed in one of two ways, depending upon whether
+the reservoir is charged by the engine itself operatively
+connected with the compressor, or by an independent
+compressor, mechanically operated.</p>
+
+<div class="figcenter" style="width: 557px;">
+<img src="images/fig_039.jpg" width="557" height="600" alt="Fig. 39." title="" />
+<span class="caption"><span class='smcap'>Fig. 39.</span>&mdash;Tangye starter.</span>
+</div>
+
+<p>In the first case, the pipe is provided with a stop-cock,
+mounted adjacent to the cylinder, and with a
+check-valve. When the engine is started and the gas
+<!--066.png--><span class='pagenum'><a name="Page_66" id="Page_66">[66]</a></span>
+cut off, the air is drawn in at each cycle and driven
+back into the reservoir during the period of compression.
+When the engine, running under these conditions
+by reason of the inertia of the fly-wheel, begins to slow
+down, the check-valve is closed and the gas-admission
+valve opened, so as to produce several explosions and to
+impart a certain speed to the engine in order to continue
+the charging of the reservoir with compressed air.
+This done, the valve on the reservoir itself is tightly
+closed, as well as the check-valve, so as to avoid any
+leakage likely to cause a fall in the reservoir's pressure.</p>
+
+<p>In the second case, which applies particularly to
+engines of more than 50 horse-power, the charging pipe
+connected with the reservoir is necessarily independent
+of the pipe by means of which the motor is started.
+The reservoir having been filled and the decompression
+cam thrown into gear, starting is accomplished:</p>
+
+<p>1. By placing the piston in starting position, which
+corresponds with a crank inclination of 10 to 20 degrees
+in the direction of the piston's movement, from the
+rear dead center, immediately after the period of compression;</p>
+
+<p>2. By opening the reservoir-valve;</p>
+
+<p>3. By allowing the compressed air to enter the
+cylinder rapidly, through the quick manipulation of
+the stop-cock, which is closed again when the impulse
+is given and reopened at the corresponding period of
+the following cycle, this operation being repeated several
+times in order to impart sufficient speed to the
+motor;<!--067.png--><span class='pagenum'>67</span></p>
+
+<p>4. By opening the gas-valve and finally closing the
+two valves of the compressed-air pipe.</p>
+
+<p>The pipes and compressed-air reservoirs should be
+perfectly tight. The reservoirs should have a capacity
+in inverse ratio to the pressure under which they are
+placed, <i>i.e.</i>, they increase in size as the pressure decreases.
+If, for example, the reservoirs should be operated
+normally at a pressure of 105 to 120 pounds per
+square inch, their capacity should be at least five or six
+times the volume of the engine-cylinder. If these reservoirs
+are charged by the engine itself, the pressure
+will always be less by 15 to 20 per cent. than that
+of the compression.<!--068.png--></p>
+
+<hr class="ChapterTopRule" />
+<!--068.png--><p><span class='pagenum'><a name="Page_68" id="Page_68">[68]</a></span></p>
+<h2><a name="CHAPTER_III" id="CHAPTER_III"></a>CHAPTER III</h2>
+
+<div class="c3">THE INSTALLATION OF AN ENGINE</div>
+
+<p>In the preceding chapter the various structural details
+of an engine have been summarized and those arrangements
+indicated which, from a general standpoint,
+seem most commendable. No particular system
+has been described in order that this manual might be
+kept within proper limits. Moreover, the best-known
+writers, such as Hutton, Hiscox, Parsell and Weed, in
+America; Aim&eacute; Witz, in France; Dugald Clerk, Frederick
+Grover, and the late Bryan Donkin, in England;
+G&uuml;ldner, Schottler, Thering, in Germany, have published
+very full descriptive works on the various types
+of engines.</p>
+
+<p>We shall now consider the various methods which
+seem preferable in installing an engine. The directions
+to be given, the author believes, have not been hitherto
+published in any work, and are here formulated, after
+an experience of fifteen years, acquired in testing over
+400 engines of all kinds, and in studying the methods
+of the leading gas-engine-building firms in the chief
+industrial centers of Europe and America.</p>
+
+<p><b>Location.&mdash;</b>The engine should be preferably located
+in a well-lighted place, accessible for inspection and
+maintenance, and should be kept entirely free from
+<!--069.png--><span class='pagenum'><a name="Page_69" id="Page_69">[69]</a></span>
+dust. As a general rule, the engine space should be enclosed.
+An engine should not be located in a cellar, on
+a damp floor, or in badly illuminated and ventilated
+places.</p>
+
+<p><b>Gas-Pipes.&mdash;</b>The pipes by which fuel is conducted
+to engines, driven by street-gas, and the gas-bags, etc.,
+are rarely altogether free from leakage. For this
+reason, the engine-room should be as well ventilated as
+possible in the interest of safety. Long lines of pipe
+between the meter and the engine should be avoided,
+for the sake of economy, since the chances for leakage
+increase with the length of the pipe. It seldom happens
+that the leakage of a pipe 30 to 50 feet long, supplying
+a 30 horse-power engine, is much less than 90 cubic feet
+per hour. The beneficial effect of short supply pipes
+between meter and engine on the running of the engine
+is another point to be kept in mind.</p>
+
+<p>An engine should be supplied with gas as cool as
+possible, which condition is seldom realized if long
+pipe lines be employed, extending through workshops,
+the temperature of which is usually higher than that of
+underground piping. On the other hand, pipes should
+not be exposed to the freezing temperature of winter,
+since the frost formed within the pipe, and particularly
+the crystalline deposition of naphthaline, reduces the
+cross section and sometimes clogs the passage. Often
+it happens that water condenses in the pipes; consequently,
+the piping should be disposed so as to obviate
+inclines, in which the water can collect in pockets. An
+accumulation of water is usually manifested by fluctuations
+<!--070.png--><span class='pagenum'><a name="Page_70" id="Page_70">[70]</a></span>
+in the flame of the burner. In places where water
+can collect, a drain-cock should be inserted. In places
+exposed to frost, a cock or a plug should be provided,
+so that a liquid can be introduced to dissolve the naphthaline.
+To insure the perfect operation of the engine,
+as well as to avoid fluctuations in nearby lights, pipes
+having a large diameter should preferably be employed.
+The cross-section should not be less than that
+of the discharge-pipe of the meter, selected in accordance
+with the prescriptions of the following table:</p>
+
+<div class="c3">GAS-METERS.</div>
+
+<div class='center'>
+<table border="1" width="600" cellpadding="4" cellspacing="0" summary="gasmeters">
+
+<tr><td>Capacity.</td>
+ <td>Normal hourly flow.</td>
+ <td>Height, inches.</td>
+ <td>Width, inches.</td>
+ <td>Depth, inches.</td>
+ <td>Diameter of pipe, inches.</td>
+ <td>Power of engine to be fed.</td>
+</tr>
+<tr>
+ <td>burners</td><td>cu. ft.</td>
+ <td>in.</td><td>in.</td><td>in.</td>
+ <td>in.</td><td>h.-p.</td>
+</tr>
+<tr>
+ <td>3</td>
+ <td>14.726</td>
+ <td>13</td><td>11</td><td>9<sup>13</sup>&frasl;<sub>16</sub></td>
+ <td>0.590</td><td><sup>1</sup>&frasl;<sub>2</sub></td>
+</tr>
+<tr>
+ <td>5</td>
+ <td>24.710</td><td>18</td>
+ <td>13<sup>3</sup>&frasl;<sub>4</sub></td><td>10<sup>5</sup>&frasl;<sub>8</sub></td>
+ <td>0.787</td><td><sup>3</sup>&frasl;<sub>4</sub></td></tr>
+<tr>
+ <td>10</td>
+ <td>49.420</td><td>21<sup>1</sup>&frasl;<sub>4</sub></td>
+ <td>18<sup>1</sup>&frasl;<sub>2</sub></td><td>12<sup>9</sup>&frasl;<sub>16</sub></td>
+ <td>0.984</td><td>1-2</td>
+</tr>
+<tr>
+ <td>20</td>
+ <td>98.840</td><td>23<sup>3</sup>&frasl;<sub>16</sub></td>
+ <td>19<sup>11</sup>&frasl;<sub>16</sub></td><td>15<sup>5</sup>&frasl;<sub>16</sub></td>
+ <td>1.181</td><td>3-4</td>
+</tr>
+<tr>
+ <td>30</td>
+ <td>148.260</td><td>25<sup>5</sup>&frasl;<sub>8</sub></td>
+ <td>21<sup>11</sup>&frasl;<sub>16</sub></td><td>18<sup>3</sup>&frasl;<sub>16</sub></td>
+ <td>1.456</td><td>5-6</td>
+</tr>
+<tr>
+<td>50</td>
+<td>247.100</td><td>29<sup>1</sup>&frasl;<sub>2</sub></td>
+<td>24<sup>5</sup>&frasl;<sub>16</sub></td><td>20<sup>7</sup>&frasl;<sub>16</sub></td>
+<td>1.592</td><td>7-10</td>
+</tr>
+<tr>
+<td>60</td>
+<td>296.520</td><td>30<sup>5</sup>&frasl;<sub>16</sub></td>
+<td>25<sup>5</sup>&frasl;<sub>8</sub></td><td>25<sup>5</sup>&frasl;<sub>8</sub></td>
+<td>1.671</td><td>11-14</td>
+</tr>
+<tr>
+<td>80</td>
+<td>395.360</td><td>33<sup>5</sup>&frasl;<sub>16</sub></td>
+<td>30<sup>5</sup>&frasl;<sub>16</sub></td><td>27<sup>1</sup>&frasl;<sub>8</sub></td>
+<td>1.968</td><td>15-19</td>
+</tr>
+<tr>
+ <td>100</td>
+ <td>494.200</td><td>35</td>
+ <td>33<sup>7</sup>&frasl;<sub>16</sub></td><td>29<sup>15</sup>&frasl;<sub>16</sub></td>
+ <td>1.968</td><td>20-25</td>
+</tr>
+<tr>
+ <td>150</td>
+ <td>741.300</td><td>40<sup>3</sup>&frasl;<sub>16</sub></td>
+ <td>40<sup>3</sup>&frasl;<sub>16</sub></td><td>33<sup>13</sup>&frasl;<sub>16</sub></td>
+ <td>&mdash;</td>
+ <td>30-40</td>
+</tr>
+</table></div>
+
+<p>The records made are exact only when the meters
+(Fig. 40) are installed and operated under normal conditions.
+Two chief causes tend to falsify the measurements
+in wet meters: (1) evaporation of the water, (2)
+the failure to have the meter level.</p>
+
+<p>Evaporation occurs incessantly, owing to the flowing
+of the gas through the apparatus, and increases with
+a rise in the temperature of the atmosphere surrounding
+the meter. Consequently this temperature must be kept
+<!--071.png--><span class='pagenum'><a name="Page_71" id="Page_71">[71]</a></span>
+down, for which reason the meter should be placed as
+near the ground as possible. The evaporation also increases
+with the volume of gas delivered. Hence the
+meter should not supply more than the volume for
+which it was intended. In order to facilitate the return
+of the water of condensation to the meter and to
+prevent its accumulation, the pipes should be inclined
+as far as possible toward the meter. The lowering of
+the water-level in the meter benefits the consumer at
+the expense of the gas company.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_040.jpg" width="600" height="366" alt="Fig. 40." title="" />
+<span class="caption"><span class='smcap'>Fig. 40.</span>&mdash;Wet gas-meter.</span>
+</div>
+
+<p>Inclination from the horizontal has an effect that
+varies with the direction of inclination. If the meter
+be inclined forward, or from left to right, the water
+can flow out by the lateral opening at the level, and incorrect
+measurements are made to the consumer's cost.</p>
+
+<p>During winter, the meter should be protected from
+cold. The simplest way to accomplish this, is to wrap
+substances around the meter which are poor conductors
+of heat, such as straw, hay, rags, cotton, and the like.
+Freezing of the water can also be prevented by the addition
+<!--072.png--><span class='pagenum'><a name="Page_72" id="Page_72">[72]</a></span>
+of alcohol in the proportion of 2 pints per burner.
+The water is thus enabled to withstand a temperature
+of about 5 degrees F. below zero. Instead of alcohol,
+glycerine in the same proportions can be employed,
+care being taken that the glycerine is neutral, in order
+that the meter may not be attacked by the acids which
+the liquid sometimes contains.</p>
+
+<div class="figcenter" style="width: 301px;">
+<img src="images/fig_041.jpg" width="301" height="400" alt="Fig. 41." title="" />
+<span class="caption"><span class='smcap'>Fig. 41.</span>&mdash;Dry gas-meter.</span>
+</div>
+
+<p><b>Dry Meters.&mdash;</b>Dry meters are employed chiefly in
+cold climates, where wet meters could be protected only
+with difficulty and where the water is likely to freeze.
+In the United States the dry meter is the type most
+widely employed. In Sweden and in Holland it is also
+generally introduced (Fig. 41).</p>
+
+<p>In the matter of accuracy of measurement there is
+little, if any, difference between wet and dry meters.
+The dry meter has the merit of measuring correctly regardless
+<!--073.png--><span class='pagenum'>73</span>
+of the fluctuations in the water level. On the
+other hand, it is open to the objection of absorbing
+somewhat more pressure than the wet meter, after having
+been in operation for a certain length of time.
+This is an objection of no great weight; for there is
+always enough pressure in the mains and pipes to
+operate a meter.</p>
+
+<div class="figcenter" style="width: 440px;">
+<img src="images/fig_042.jpg" width="440" height="600" alt="Fig. 42." title="" />
+<span class="caption"><span class='smcap'>Fig. 42.</span>&mdash;Section through a dry gas-meter.</span>
+</div>
+
+<p>In many cases, where the employment of non-freezing
+liquids is necessary, the dry meter may be used to
+<!--074.png--><span class='pagenum'>74</span>
+advantage, since all such liquids have more or less corroding
+effect on sheet lead and even tin, depending
+upon the composition of the gas.</p>
+
+<div class="figcenter" style="width: 352px;">
+<img src="images/fig_043.jpg" width="352" height="600" alt="Fig. 43." title="" />
+<span class="caption"><span class='smcap'>Fig. 43.</span>&mdash;Section through a dry gas-meter.</span>
+</div>
+
+<p>The dry meter comprises two bellows, operating in
+a casing divided into two compartments by a central
+partition. The gas is distributed on one or the other
+side of the bellows, by slides <i>B</i>. The slides <i>B</i> are provided
+with cranks <i>E</i>, controlled by levers <i>M</i>, actuated
+by transmission shafts <i>O</i>, driven by the bellows.
+The meter is adjusted by a screw which changes the
+throw of the cranks <i>E</i> and consequently affects the bellows.
+<!--075.png--><span class='pagenum'><a name="Page_75" id="Page_75">[75]</a></span>
+The movement of the crank-shaft <i>D</i> is transmitted
+to the indicating apparatus. In order to obviate
+any leakage, this shaft passes through a stuffing-box,
+<i>G</i>. The diagrams (Figs. 42-43) show the construction
+of a dry meter, the arrows indicating the course taken
+by the gas.</p>
+
+<div class="figcenter" style="width: 454px;">
+<img src="images/fig_044.jpg" width="454" height="600" alt="Fig. 44." title="" />
+<span class="caption"><span class='smcap'>Fig. 44.</span>&mdash;Rubber bag to prevent fluctuations of
+the ignition flame.</span>
+</div>
+
+<!--076.png--><p><span class='pagenum'>76</span></p>
+<div class="figcenter" style="width: 391px;">
+<img src="images/fig_045.jpg" width="391" height="600" alt="Fig. 45." title="" />
+<span class="caption"><span class='smcap'>Fig. 45.</span>&mdash;Rubber bags on gas-pipes.</span>
+</div>
+
+<p>Care should be taken to provide the gas-pipe with
+a drain-cock, at a point near the engine. By means of
+this cock, any air in the pipe can be allowed to
+<!--077.png--><span class='pagenum'><a name="Page_77" id="Page_77">[77]</a></span>
+escape before starting; otherwise the engine can be set
+in motion only with difficulty. If the engine be provided
+with an incandescent tube, the gas-supply pipe of
+the igniter should be fitted with a small rubber pouch
+or bag, in order to obviate fluctuations in the burner
+flame, caused by variations in the pressure (Fig. 44).
+As a general rule, the supply-pipe should be connected
+with the main pipe on the forward side of the bags and
+gas-governors. The main pipe and all other piping
+near the engine should extend underground, so that
+free access to the motor from all sides can be obtained,
+without possibility of injury.</p>
+
+<p><b>Anti-pulsators, Bags, Pressure-Regulators.&mdash;</b>The
+most commonly employed means of preventing fluctuation
+of nearby lights, due to the sharp strokes of the engine,
+consists in providing the gas-supply pipe with rubber
+bags (Fig. 45), which form reservoirs for the gas
+and, by reason of their elasticity, counteract the effect
+produced by the suction of the engine. Nevertheless, in
+order to insure a supply of gas at a constant pressure,
+which is necessary for the perfect operation of the engine,
+there are generally used, in addition to the bags,
+devices called gas-governors, or anti-pulsators (Fig. 46).</p>
+
+<p>Although these devices are constructed in different
+ways, the underlying principle is the same in all. They
+comprise a metallic casing, containing a flexible diaphragm
+of rubber or of some fabric impermeable to
+gas. Suction of the engine creates a vacuum in the casing.
+The diaphragm bends, thereby actuating a valve,
+<!--078.png--><span class='pagenum'><a name="Page_78" id="Page_78">[78]</a></span>
+which cuts off the gas supply. During the three following
+periods (compression, explosion, and exhaust)
+the gas, by reason of its pressure on the diaphragm,
+opens the valve and fills the casing, ready for the next
+suction stroke.</p>
+
+<div class="figcenter" style="width: 383px;">
+<img src="images/fig_046.jpg" width="383" height="600" alt="Fig. 46." title="" />
+<span class="caption"><span class='smcap'>Fig. 46.</span>&mdash;An anti-pulsator.</span>
+</div>
+
+<p>Other devices, which are never sold with the engine,
+but are rendered necessary by reason of the conditions
+imposed by the gas supply are sold under the name
+"pressure-regulators" (Fig. 47). They consist of a
+bell, floating in a reservoir containing water and glycerine
+(or mercury), and likewise actuate a valve
+which partially controls the flow of gas. This valve
+being balanced, its mechanical action is the more certain.
+Such devices are very effective in maintaining
+the steadiness of lights. On the other hand, they are
+often an obstacle to the operation of the engine because
+they reduce the flow and pressure of the gas too
+much. In order to obviate this difficulty, a pressure-regulator
+should be chosen with discrimination, and of
+<!--079.png--><span class='pagenum'><a name="Page_79" id="Page_79">[79]</a></span>
+sufficiently large size to insure the maintenance of an
+adequate supply of gas to the engine. Frequent examinations
+should be made to ascertain if the bell of
+the regulator is immersed in the liquid. In the case of
+anti-pulsators, care should be taken that they are not
+spattered with oil, which has a disastrous effect on rubber.
+Anti-pulsators are generally mounted about 4
+inches from a wall, in order that the diaphragm may
+be actuated by hand, if need be.</p>
+
+<div class="figcenter" style="width: 466px;">
+<img src="images/fig_047.jpg" width="466" height="600" alt="Fig. 47." title="" />
+<span class="caption"><span class='smcap'>Fig. 47.</span>&mdash;A pressure-regulator.</span>
+</div>
+
+<p><b>Precautions.&mdash;</b>In order not to strain the rubber of
+the bags or of the anti-pulsators, it is advisable to place
+a stop-cock in advance of these devices so that they can
+not be filled while the motor is at rest.</p>
+
+<p>The capacity of the rubber bags that can be bought
+<!--080.png--><span class='pagenum'><a name="Page_80" id="Page_80">[80]</a></span>
+in the market being limited, it is necessary to place one,
+two, or three extra bags in series (Figs. 48 and 49), for
+large pipes; but it should be borne in mind that the
+total section of the branch pipes should be at least equal
+to that of the main pipe. It is also advisable to extend
+the tube completely through the bag as shown in Figs.
+48 and 49.</p>
+
+<div class="figcenter" style="width: 573px;">
+<img src="images/fig_048.jpg" width="573" height="600" alt="Fig. 50." title="" />
+<span class="caption"><span class="smcap">Figs. 48-49.</span>&mdash;Arrangement of rubber bags.</span>
+</div>
+
+<p>If there be two branch pipes the minimum diameter
+<!--081.png--><span class='pagenum'><a name="Page_81" id="Page_81">[81]</a></span>
+which meets this requirement is ascertained as follows:
+Draw to any scale a semicircle having a diameter
+equal or proportional to that of the main pipe (Fig.
+50). The sides of the isosceles triangle inscribed within
+this semicircle give the minimum diameter of each
+of the branch pipes.</p>
+
+<p>Sometimes engines are provided with a cock having
+an arrangement by means of which the gas feed is permanently
+regulated, according to the quality and pressure
+of the gas and according to the load at which the
+engine is to run. This renders it possible to open the
+cock always to the same point (Fig. 51).</p>
+
+<div class="figcenter" style="width: 400px;">
+<img src="images/fig_050.jpg" width="400" height="280" alt="Fig. 50." title="" />
+<span class="caption"><span class='smcap'>Fig. 50.</span></span>
+</div>
+
+<div class="figcenter" style="width: 400px;">
+<img src="images/fig_051.jpg" width="400" height="367" alt="Fig. 51." title="" />
+<span class="caption"><span class='smcap'>Fig. 51.</span></span>
+</div>
+
+<p><b>Air Suction.&mdash;</b>In a special chapter the precautions to
+be taken to counteract the influence of the suction of the
+engine in causing vibration will be treated. The manner
+in which the suction of air is effected necessarily
+has as marked an influence on the operation of the engine
+as the supply of gas, since air and gas constitute
+the explosive mixture.</p>
+
+<p>Resistance to the suction of air should be carefully
+<!--082.png--><span class='pagenum'><a name="Page_82" id="Page_82">[82]</a></span>
+avoided, for which reason the length of the pipe should
+be reduced to a minimum, and its cross-section kept at
+least equal to that of the air inlet of the engine. Since
+the quality of street-gas varies with each city, the
+proper proportions of gas and air are not constant. In
+order that these proportions may be regulated, it is a
+matter of some importance to fit some suitable device
+on the pipe. Good engines are provided with a plug
+or flap valve. Generally the air-pipe terminates either
+in the hollowed portion of the frame, or in an independent
+pot, or air chest. The first arrangement is not
+to be recommended for engines over 20 to 25 horse-power.
+Accidents may result, such as the breaking of
+the frame by reason of back firing, of which more will
+be said later. If an independent chest be employed, its
+closeness to the ground renders it possible for dust
+easily to pass through the air-holes in the walls at the
+moment of suction, and even to enter the cylinder,
+where its presence is particularly harmful, leading, as
+it does, to the rapid wear of the rubbing surfaces. This
+evil can be largely remedied by filling the air-chest
+with cocoa fiber or even wood fiber, provided the latter
+does not become packed down so as to prevent the air
+from passing freely. Such fibers act as air-filters. Regular
+cleaning or renewal of the fiber protects the cylinder
+from wear. In a general way, care should be
+taken, before fitting both the gas and air pipes, to tap
+the pipes, elbows, and joints lightly with a hammer on
+the outside in order to loosen whatever rust or sand
+may cling to the interior; otherwise this foreign matter
+<!--083.png--><span class='pagenum'><a name="Page_83" id="Page_83">[83]</a></span>
+may enter the cylinder and cause perturbations in the
+operation of the engine. Under all circumstances, care
+should be taken not to place the end of the air-pipe
+under the floor or in an enclosed space, because leakage
+may occur, due to the bad seating of the air-valve, thereby
+producing a mixture which may explode if the
+flame leaps back, as we shall see in the discussion of
+suction by pipes terminating in the hollow of the frame.
+On the other hand, sand or sawdust should not be
+sprinkled on the floor.</p>
+
+<p><b>Exhaust.&mdash;</b>For the exhaust, cast-iron or drawn pipes
+as short as possible should be used. Not only the power
+of the engine, but also its economic consumption, can be
+markedly affected by the employment of long and bent
+pipes. Resistance to the exhaust of the products of
+combustion not only causes an injurious counter-pressure,
+but also prevents the clearing of the cylinder of
+burnt gases, which contaminate the aspired mixture
+and rob it of much of its explosiveness. The necessity
+of evacuating the cylinder as completely as possible is,
+nevertheless, not always reconcilable with local surroundings.
+To a certain extent, the objections to long
+exhaust-pipes are overcome by rigorously avoiding the
+use of elbows. Gradual curves are preferable. In the
+case of very long pipes it is advisable to increase their
+diameter every 16 feet from the exhaust. The exhaust-chest
+should be placed as near as possible to the engine;
+it should never be buried; for the joints of the inlet and
+outlet pipes of the exhaust-chest should be easily accessible,
+so that they may be renewed when necessary. The
+<!--084.png--><span class='pagenum'>84</span>
+author recommends the placing of the exhaust-chest in
+a masonry pit, which can be closed with a sheet-metal
+cover. For engines of 20 horse-power and upward,
+these joints should be entirely of asbestos. Pipes
+screwed directly into the casting are liable to rust. Exposed
+as they are to the steam or water of the exhaust,
+they cannot be detached.</p>
+
+<div class="figcenter" style="width: 495px;">
+<img src="images/fig_052.jpg" width="495" height="600" alt="Fig. 52." title="" />
+<span class="caption"><span class='smcap'>Fig. 52.</span>&mdash;Method of mounting pipes.</span>
+</div>
+
+<p>The water, which results from the combination of
+the hydrogen of the gas with the oxygen of the air, is
+deposited in most cases at the bottom of the exhaust-chest.
+It is advisable to fit a plug or iron cock in the
+base of the chest. Alkaline or acid water will always
+corrode a bronze cock. In order that the pipes may
+not also be attacked, they are not disposed horizontally,
+<!--085.png--><span class='pagenum'><a name="Page_85" id="Page_85">[85]</a></span>
+but are given a slight incline toward the point where
+the water is drained off. If pipes of some length be
+employed, they should be able to expand freely without
+straining the joints, as shown in the accompanying
+diagram (Fig. 52), in which the exhaust-chest
+rests on iron rollers which permit a slight displacement.</p>
+
+<p>For the sake of safety, at least that portion of the
+piping which is near the engine should be located at a
+proper distance from woodwork and other combustible
+material. By no means should the exhaust discharge
+into a sewer or chimney, even though the sewer or
+chimney be not in use; for the unburnt gases may be
+trapped, and dangerous explosions may ensue at the
+moment of discharge.</p>
+
+<p>The joints or threaded sleeves employed in assembling
+the exhaust-pipe should be tested for tightness.
+The combined action of the moisture and heat causes
+the metal to rust and to deteriorate very rapidly at
+leaky spots.</p>
+
+<p>When several engines are installed near one another,
+each should be provided with a special exhaust-pipe;
+otherwise it may happen, when the engines are all
+running at once, that the products of combustion discharged
+by the one may cause a back pressure detrimental
+to the exhaust of the next.</p>
+
+<p>It is possible to employ a pipe common to all the exhausts
+if the pipe starts from a point beyond the exhaust-chests,
+in which case Y-joints and not T-joints
+are to be used.
+<!--086.png--><span class='pagenum'><a name="Page_86" id="Page_86">[86]</a></span></p>
+
+<p>The manner of securing the pipes to walls by means
+of detachable hangers, lined with asbestos, is shown in
+a general way in the accompanying Fig. 53. The
+object of this arrangement is to render detachment
+easy and to prevent the transmission of shocks to the
+masonry.</p>
+
+<p>The precautions to be taken for muffling the noise of
+the exhaust will be discussed later.</p>
+
+<p>The end of the exhaust-pipe should be slightly
+curved down in order to prevent the entrance of rain.
+Exhaust-pipes are subjected to considerable vibration,
+due to the sudden discharge of the gases. To protect
+the joints, the pipes should be rigidly fastened in place.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_053.jpg" width="600" height="546" alt="Fig. 53." title="" />
+<span class="caption"><span class='smcap'>Fig. 53.</span>&mdash;Method of securing pipes to walls.</span>
+</div>
+
+<p><b>Legal Authorization.&mdash;</b>In most countries gas-engines
+may be installed only in accordance with the
+provision of general or local laws, which impose certain
+conditions. These laws vary with different localities,
+for which reason they are not discussed here.</p>
+
+<hr class="ChapterTopRule" />
+<!--087.png--><p><span class='pagenum'><a name="Page_87" id="Page_87">[87]</a></span></p>
+
+<h2><a name="CHAPTER_IV" id="CHAPTER_IV"></a>CHAPTER IV</h2>
+
+<div class="c3">FOUNDATION AND EXHAUST</div>
+
+<p>The reader will remember from what has already
+been said that a gas-engine is a motor which, more than
+any other, is subjected to forces, suddenly and repeatedly
+exerted, producing violent reactions on the
+foundation. It follows that the foundation must be
+made particularly resistant by properly determining its
+shape and size and by carefully selecting the material
+of which it is to be built.</p>
+
+<p><b>The Foundation Materials.&mdash;</b>Well-hardened brick
+should be used. The top course of bricks should be
+laid on edge. It is advisable to increase the stability
+of the foundation by longitudinally elongating it toward
+the base, as shown in the accompanying diagram
+(Fig. 54).</p>
+
+<p>As a binding material, only mortar composed of
+coarse sand or river sand and of good cement, should
+be used. Instead of coarse sand, crushed slag, well-screened,
+may be employed. The mortar should consist
+of <sup>2</sup>&frasl;<sub>3</sub> slag and <sup>1</sup>&frasl;<sub>3</sub> cement. Oil should not in any
+way come into contact with the mortar; it may percolate
+through the cement and alter its resistant qualities.</p>
+
+<p>As in the construction of all foundations, care should
+be taken to excavate down to good soil and to line the
+<!--088.png--><span class='pagenum'><a name="Page_88" id="Page_88">[88]</a></span>
+bottom with concrete, in order to form a single mass of
+artificial stone. A day or two should be allowed for
+the masonry to dry out, before filling in around it.</p>
+
+<p>When the engine is installed on the ground floor
+above a vaulted cellar, the foundation should not rest
+directly on the vault below or on the joists, but should
+be built upon the very floor of the cellar, so that it
+passes through the planking of the ground floor without
+contact.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_054.jpg" width="600" height="545" alt="Fig. 54." title="" />
+<span class="caption"><span class='smcap'>Fig. 54.</span>&mdash;Method of building the foundation.</span>
+</div>
+
+<p>When the engine is to be installed on a staging, the
+<!--089.png--><span class='pagenum'><a name="Page_89" id="Page_89">[89]</a></span>
+method of securing it in place illustrated in Fig. 55
+should be adopted.</p>
+
+<p>Although a foundation, built in the manner described,
+will fulfill the usual conditions of an industrial
+installation, it will be inadequate for special cases in
+which trepidation is to be expected. Such is the case
+when engines are to be installed in places where, owing
+to the absence of factories, it is necessary to avoid
+all nuisance, such as noise, trepidations, odors, and
+the like.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_055.jpg" width="600" height="344" alt="Fig. 55." title="" />
+<span class="caption"><span class='smcap'>Fig. 55.</span>&mdash;Elevated foundation.</span>
+</div>
+
+<p><b>Vibration.&mdash;</b>In order to prevent the transmission of
+vibration, the foundation should be carefully insulated
+from all neighboring walls. For this purpose various
+insulating substances called "anti-vibratory" are to be
+recommended. Among these may be mentioned horsehair,
+felt packing, cork, and the like. The efficacy
+of these substances depends much on the manner in
+which they are applied. It is always advisable to interpose
+a layer of one of these substances, from one to four
+inches thick, between the foundation and the surrounding
+soil, the thickness varying with the nature of the
+<!--090.png--><span class='pagenum'><a name="Page_90" id="Page_90">[90]</a></span>
+material used and the effect to be obtained. Between
+the bed of concrete, mentioned previously, and the
+foundation-masonry and between the foundation and
+the engine-frame, a layer of insulating material may
+well be placed. Preference is to be given to substances
+not likely to rot or at least not likely to lose their insulating
+property, when acted upon by heat, moisture
+or pressure.</p>
+
+<p>Here it may not be amiss to warn against the utilization
+of cork for the bottom of the foundation; for water
+may cause the cork to swell and to dislocate the foundation
+or destroy its level.</p>
+
+<p>The employment of the various substances mentioned
+does not entail any great expense when the
+foundations are not large and the engines are light.
+But the cost becomes considerable when insulating material
+is to be employed for the foundation of a 30 to 50
+horse-power engine and upwards. For an engine of
+such size the author recommends an arrangement as
+simple as it is efficient, which consists in placing the
+foundation of the engine in a veritable masonry basin,
+the bottom of which is a bed of concrete of suitable
+thickness. The foundation is so placed that the lateral
+surfaces are absolutely independent of the supporting-walls
+of the basin thus formed. Care should be taken
+to cover the bottom with a layer of dry sand, rammed
+down well, varying in thickness with each case. This
+layer of sand constitutes the anti-vibratory material and
+confines the trepidations of the engine to the foundation.
+<!--091.png--><span class='pagenum'><a name="Page_91" id="Page_91">[91]</a></span></p>
+
+<p>As a result of this arrangement, it should be observed
+that, being unsupported laterally, the foundation
+should be all the more resistant, for which reason
+the base-area and weight should be increased by 30 to
+40 per cent. The expense entailed will be largely offset
+by saving the cost of special anti-vibratory substances.
+In places liable to be flooded by water, the
+basin should be cemented or asphalted.</p>
+
+<p>When the engine is of some size and is intended for
+the driving of one or more dynamos which may themselves
+give rise to vibrations, the dynamos are secured
+directly to the foundation of the engine, which is extended
+for that purpose, so that both machines are carried
+solidly on a single base.</p>
+
+<p>The foregoing outline should not lead the proprietor
+of a plant to dispense with the services of experts,
+whose long experience has brought home to them the
+difficulties to be overcome in special cases.</p>
+
+<p>It should here be stated, as a general rule, that the
+bricks should be thoroughly moistened before they are
+laid in order that they may grip the mortar.</p>
+
+<p>After having been placed on the foundation and
+roughly trimmed with respect to the transmission devices,
+the engine is carefully leveled by means of hardwood
+wedges driven under the base. This done, the
+bolts are sealed by very gradually pouring a cement
+wash into the holes, and allowing it to set. When the
+holes are completely filled and the bolts securely fastened
+in place, a shallow rim, or edge of clay, or sand
+is run around the cast base, so as to form a small box
+<!--092.png--><span class='pagenum'><a name="Page_92" id="Page_92">[92]</a></span>
+or trough, in which cement is also poured for the purpose
+of firmly binding the engine frame and foundation
+together. When, as in the case of electric-light
+engines, single extra-heavy fly-wheels are employed,
+provided with bearings held in independent cast supports,
+the following rule should be observed to prevent
+the overheating due to unlevelness, which usually occurs
+at the bushings of these bearings: That part of the
+foundation which is to receive such a support should
+rest directly on the concrete bed and should be rigidly
+connected at the bottom with the main foundation.
+When the foundation is completely blocked up, the fly-wheel
+bearing with its support is hung to the crank-shaft;
+and not until this is effected is the masonry at
+the base of the support completed and rigidly fixed in
+its proper position.</p>
+
+<p>For very large engines, the foundation-bolts should
+be particularly well sealed into the foundation. In
+order to attain this end the bricks are laid around the
+bolt-holes, alternately projected and retracted as shown
+in Fig. 54. Broken stone is then rammed down around
+the fixed bolt; in the interstices cement wash is poured.</p>
+
+<p><b>Air Vibration, etc.&mdash;</b>Vibration due chiefly to the
+transmission of noises and the displacement of air by
+the piston should not be confused with the trepidations
+previously mentioned.</p>
+
+<p>The noise of an engine is caused by two distinct
+phenomena. The one is due to the transmitting
+properties of the entire solid mass constituting
+the frame, the foundation, and the soil. The other is
+<!--093.png--><span class='pagenum'>93</span>
+due to vibrations transmitted to the air. In both cases,
+in order to reduce the noise to a minimum, the moving
+parts should be kept nicely adjusted, and above all,
+shocks avoided, the more harmful of which are caused
+by the play between the joint at the foot of the connecting-rod
+and the piston-pin, and between the head of the
+connecting-rod and the crank-shaft.</p>
+
+<p>Although smooth running of the engine may be assured,
+there is always an inherent drawback in the
+rapid reciprocating movement of the piston. In large,
+single-acting gas-engines, a considerable displacement
+of air is thus produced. In the case of a forty horse-power
+engine having a cylinder diameter and piston-stroke
+respectively of 13<sup>3</sup>&frasl;<sub>4</sub> inches and 21<sup>3</sup>&frasl;<sub>5</sub> inches, it
+is evident that at each stroke the piston will displace
+about 2 cubic feet of air, the effect of which will be
+doubled when it is considered that on the forward
+stroke back pressure is created and on the return stroke
+suction is produced.</p>
+
+<p>The air motion caused by the engine is the more
+readily felt as the engine-room is smaller. If the room,
+for example, be 9 feet by 15 feet by 8 feet, the volume
+will be 1,080 cubic feet. From this it follows that the
+2 cubic feet of air in the case supposed will be alternately
+displaced six times each second, which means
+the displacement of 12 cubic feet at short intervals
+with an average speed of 550 feet per minute. Such
+vibrations transmitted to halls or neighboring rooms
+are due entirely to the displacement of the air.</p>
+
+<p>In installations where the air-intake of the engine is
+<!--094.png--><span class='pagenum'><a name="Page_94" id="Page_94">[94]</a></span>
+located in the engine-room, a certain compensation is
+secured, at the period of suction, between the quantity
+of air expelled on the forward stroke of the piston and
+the quantity of air drawn into the cylinder. From this
+it follows that the vibration caused by the movement
+of the air is felt less and occurs but once for two revolutions
+of the engine.</p>
+
+<p>This phenomenon is very manifest in narrow rooms
+in which the engine happens to be installed near glass
+windows. By reason of the elasticity of the glass, the
+windows acquire a vibratory movement corresponding
+in period with half the number of revolutions of the
+engine. It follows from the preceding that, in order to
+do away with the air vibration occasioned by the piston
+in drawing in and forcing out air in an enclosed space,
+openings should be provided for the entrance of large
+quantities of air, or a sufficient supply of air should
+be forced in by means of a fan.</p>
+
+<p>The author ends this section with the advice that all
+pipes in general and the exhaust-pipe in particular be
+insulated from the foundation and from the walls
+through which they pass as well as from the ground,
+as metal pipes are good conductors of sound and liable
+to carry to some distance from the engine the sounds
+of the moving parts.</p>
+
+<p><b>Exhaust Noises.&mdash;</b>Among the most difficult noises to
+muffle is that of the exhaust. Indeed, it is the exhaust
+above all that betrays the gas-engine by its discharge to
+the exterior through the exhaust-pipe. The most commonly
+employed means for rendering the exhaust less
+<!--095.png--><span class='pagenum'><a name="Page_95" id="Page_95">[95]</a></span>
+perceptible consists in extending the pipe upward as
+far as possible, even to the height of the roof. This is
+an easy way out of the difficulty; but it has a bad effect
+on the operation of the engine. It reduces the power
+generated and increases the consumption, as will be explained
+in a special paragraph.</p>
+
+<p>Expansion-boxes, more commonly called exhaust-mufflers,
+considerably deaden the noise of explosion by
+the use of two or three successive receptacles. But this
+remedy is attended with the same faults that mark the
+use of extremely long pipes. The best plan is to mount
+a single exhaust-muffler near the discharge of the engine
+in the engine-room itself, where it will serve at
+least the purpose of localizing the sound.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_056.jpg" width="600" height="369" alt="Fig. 56." title="" />
+<span class="caption"><span class='smcap'>Fig. 56.</span>&mdash;Exhaust-muffler.</span>
+</div>
+
+<p>The employment of pipes of sufficiently large cross-section
+to constitute expansion-boxes in themselves will
+also muffle the exhaust. A more complete solution of
+the problem is obtained by causing the exhaust-pipe,
+<!--096.png--><span class='pagenum'><a name="Page_96" id="Page_96">[96]</a></span>
+after leaving the muffler, to discharge into a masonry
+trough having a volume equal to twelve times that of
+the engine-cylinder (Fig. 56). This trough should
+be divided into two parts, separated by a horizontal
+iron grating. Into the lower part, which is empty, the
+exhaust-pipe discharges; in the upper part, paving-blocks
+or hard stones not likely to crumble with the
+heat, are placed. Between this layer of stones and the
+cover it is advisable to leave a space equal to the first.
+Here the gases may expand after having been divided
+into many parts in passing through the spaces left between
+adjacent stones. The trough should not be
+closed by a rigid cover; for, although efficient muffling
+may be attained, certain disadvantages are nevertheless
+encountered. It may happen that in a badly regulated
+engine, unburnt gases may be discharged into this
+trough, forming an explosive mixture which will be
+ignited by the next explosion, causing considerable
+damage. Still, the explosion will be less dangerous
+than noisy. It may be mentioned in passing that this
+disadvantage occurs rarely.</p>
+
+<p>A second arrangement consists in superposing the
+end of the exhaust-pipe upon a casing of suitable size,
+which casing is partitioned off by several perforated
+baffle-plates. This casing is preferably made of wood,
+lined with metal, so that it will not be resonant. The
+size of the casing, the number of partitions and their
+perforations, and the manner of disposing the partitions
+have much to do with the result to be obtained.
+Here again the experience of the expert is of use.
+<!--097.png--><span class='pagenum'><a name="Page_97" id="Page_97">[97]</a></span></p>
+
+<p>Various other systems are employed, depending upon
+the particular circumstances of each case. Among
+these systems may be mentioned those in which the pipe
+is forked at its end to form either a yoke (Fig. 57) or
+a double curve, each branch of which terminates in a
+muffler (Fig. 58).</p>
+
+<div class="figcenter" style="width: 277px;">
+<img src="images/fig_057.jpg" width="277" height="500" alt="Fig. 57." title="" />
+<span class="caption"><span class='smcap'>Fig. 57.</span></span>
+</div>
+
+<div class="figcenter" style="width: 341px;">
+<img src="images/fig_058.jpg" width="341" height="400" alt="Fig. 58." title="" />
+<span class="caption"><span class='smcap'>Fig. 58.</span>&mdash;Two types of exhaust-mufflers.</span>
+</div>
+
+<p>It should be observed that, under ordinary conditions,
+noises heard as hissing sounds are often due to the
+presence of projections, or to distortion of the pipes
+near the discharge opening. Consequently, in connecting
+the pipes, care should be taken that the joints or
+seams have no interior projections. Occasionally,
+water may be injected into the exhaust-muffler in order
+to condense the vapors of the exhaust, the result being
+a deadening of the noises; but in order to be truly efficient
+this method should be employed with discretion,
+for which reason the advice of an expert is of value.</p>
+
+<hr class="ChapterTopRule" />
+<!--098.png--><p><span class='pagenum'><a name="Page_98" id="Page_98">[98]</a></span></p>
+<h2><a name="CHAPTER_V" id="CHAPTER_V"></a>CHAPTER V</h2>
+
+<div class="c3">WATER CIRCULATION</div>
+
+<p>Circulation of water in explosion-engines is one of
+the essentials of their perfect operation. Two special
+cases are encountered. In the one the jacket of the engine
+is supplied with running water; in the other, reservoirs
+are employed, the circulation being effected
+simply by the difference in specific gravity in a thermo-siphon
+apparatus. Coolers are also used.</p>
+
+<p><b>Running Water.&mdash;</b>A water-jacket fed from a constant
+source of running water, such as the water mains
+of a town, is certainly productive of the best results, the
+supply, moreover, being easily regulated; but the system
+is not widely used because the water runs away and
+is entirely lost. If running water be employed, the outlet
+of the jacket is so disposed that the water gushes out
+immediately on leaving the cylinder, and that the flow
+is visible and accessible, in order that the temperature
+may be tested by the hand. Apart from the relatively
+great cost of water in towns, the use of running water
+is objectionable on account of its chemical composition.
+Though it may be clear and limpid, it frequently
+contains lime salts, carbonates, sulphates, and silicates
+which are precipitated by reason of the sudden change
+of temperature to which the water is subjected as it
+<!--099.png--><span class='pagenum'><a name="Page_99" id="Page_99">[99]</a></span>
+comes into contact with the walls of the cylinder. That
+part of the water-jacket surrounding the head or explosion-chamber,
+where the temperature is necessarily the
+highest, becomes literally covered with calcareous incrustations,
+which are the more harmful because they
+are bad conductors of heat and because they reduce and
+even obstruct the passage exactly at the point where the
+water must circulate most freely to do any good. If the
+circulating water be pumped into the jacket, it is preferable,
+wherever possible, to use cistern water, which is
+not likely to contain lime salts in suspension. If river
+water be used, it should be free from the objections
+already mentioned, which are all the more grave if the
+water be muddy, as sometimes happens. The water-jacket
+can be easily freed from all non-adhering deposits
+by flushing it periodically through the medium
+of a conveniently placed cock. It is always preferable
+to pass the water through a reservoir where its impurities
+can settle, before it flows to the cylinder. In the
+case considered, the water usually has an average temperature
+of 54 to 60 degrees F., under which condition
+the hourly flow should be at least 5<sup>1</sup>&frasl;<sub>2</sub> gallons per horse-power
+per hour, the temperature rising at the outlet-pipe
+of the cylinder to 140 and 158 degrees F., which
+should not be surpassed. However, in engines working
+with high compression, 104 to 122 degrees F. should
+not be exceeded.</p>
+
+<p>If the water-jacket be fed by a reservoir, it is essential
+that the reservoir comply with the following conditions:
+<!--100.png--><span class='pagenum'><a name="Page_100" id="Page_100">[100]</a></span></p>
+
+<p>In horizontal engines the water-inlet is always
+located in the base of the cylinder, while the outlet is
+located at the top. By providing the inlet-pipe extending
+to the cylinder with a cock, the circulation of water
+can be regulated to correspond with the work performed
+by the engine. Another cock at the end of the
+outlet-pipe near the reservoir serves, in conjunction
+with the first, to arrest the circulating water. When the
+weather is very cold or when the cylinder must be
+repaired, these two cocks may be closed, and the pipe
+and water-jacket of the cylinder drained by means of
+the drain-cock <i>V</i> (Fig. 59), mounted at the inlet of the
+engine's water-jacket. In order that the pressure of
+the atmosphere may not prevent the flowing of the
+water, the highest part of the pipe is provided with a
+small tube, <i>T</i>, communicating with the atmosphere.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_059.jpg" width="600" height="430" alt="Fig. 59." title="" />
+<span class="caption"><span class='smcap'>Fig. 59.</span>&mdash;Thermo-siphon cooling system.</span>
+</div>
+
+<p>On account of the importance of preventing losses
+<!--101.png--><span class='pagenum'><a name="Page_101" id="Page_101">[101]</a></span>
+of the charge in the pipes the author recommends the
+utilization of sluice-valves of the type shown in Fig.
+60, instead of the usual cone or plug type.</p>
+
+<div class="figcenter" style="width: 551px;">
+<img src="images/fig_060.jpg" width="551" height="600" alt="Fig. 60." title="" />
+<span class="caption"><span class='smcap'>Fig. 60.</span>&mdash;Vanne sluice-cock.</span>
+</div>
+
+<p><b>Water-Tanks.&mdash;</b>The reservoir is mounted in such a
+way that its base is flush with the top of the cylinder; it
+should be as near as possible to the cylinder in order to
+obviate the use of long inlet and return pipes. This
+fact, however, does not necessarily render it advisable
+to place the reservoir in the engine-room; for such a
+disposition is doubly disadvantageous in so far as it
+does not permit a sufficiently rapid cooling of the circulating
+water by reason of the high temperature of the
+<!--102.png--><span class='pagenum'><a name="Page_102" id="Page_102">[102]</a></span>
+surrounding air, and in so far as it is liable to cause the
+formation of vapors which injuriously affect the engine.
+Consequently, the reservoir should be placed in
+as cool a place as possible, preferably even in the open
+air; for the water is not likely to freeze, except when
+it has been allowed to stand for a considerable time.
+The reservoir should be left uncovered so as to facilitate
+cooling by the liberation of the vapors formed on
+the surface of the water.</p>
+
+<p>Circulation being effected solely by the difference
+in specific gravity or density between the warmer water
+emerging from the cylinder and the cooler water which
+flows in from the reservoir, the slightest obstruction
+will impede the flow. Hence, the cross-section of the
+pipes should not be less than that of the inlet and outlet
+openings of the cylinder of the engine. Good circulation
+cannot be attained if the water must overcome inclines
+or obstacles in the pipes themselves. Instead of
+elbows, long curves of great radius, limited to the
+smallest possible number, should be employed. This is
+particularly true of the return-pipe extending from
+the cylinder back to the reservoir. For this pipe a
+minimum incline of 10 to 15 per cent. should be allowed,
+in order that the water may run up into the
+reservoir. The height of the water in the reservoir
+should be from 2 to 4 inches above the discharge of the
+return-pipe. In order to maintain this level it is advisable
+to use some automatic device such as a float-valve,
+in which case the reservoir should not be allowed to
+become too full.
+<!--103.png--><span class='pagenum'><a name="Page_103" id="Page_103">[103]</a></span></p>
+
+<div class="figcenter" style="width: 420px;">
+<img src="images/fig_061.jpg" width="420" height="600" alt="Fig. 61." title="" />
+<span class="caption"><span class='smcap'>Fig. 61.</span>&mdash;Correct arrangement of tanks and
+piping.</span>
+</div>
+
+<p>The size of a reservoir is determined by the engine;
+it should be large enough to enable the engine to run
+smoothly at its maximum load for several hours consecutively.
+Under these conditions, the reservoir
+<!--104.png--><span class='pagenum'>104</span>
+should have a capacity of 45 to 55 gallons per horse-power
+for engines with "hit-and-miss" admission, and
+55 to 65 gallons for engines controlled by variable admission.
+It is not advisable to employ reservoirs having
+a capacity of more than 330 to 440 gallons, the
+usual diameter being about 3 feet.</p>
+
+<div class="figcenter" style="width: 565px;">
+<img src="images/fig_062.jpg" width="565" height="600" alt="Fig. 62." title="" />
+<span class="caption"><span class='smcap'>Fig. 62.</span>&mdash;Incorrect arrangement of tanks
+and piping.</span>
+</div>
+
+<p>If the power of the engine be such that several
+reservoirs are necessary, then the reservoirs should be
+connected in such a manner that the top of the first
+communicates with the bottom of the next and so on,
+<!--105.png--><span class='pagenum'><a name="Page_105" id="Page_105">[105]</a></span>
+the first reservoir receiving the water as it comes from
+the cylinder (Fig. 61).</p>
+
+<p>Intercommunication of the reservoirs by means of a
+common top tube (<i>a</i>) is objectionable; and simultaneous
+intercommunication at top and bottom (<i>a</i> and <i>b</i>)
+is ineffective, so far as one of the reservoirs is concerned
+(Fig. 62).</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_063.jpg" width="600" height="444" alt="Fig. 63." title="" />
+<span class="caption"><span class='smcap'>Fig. 63.</span>&mdash;Tanks connected by inclined pipes.</span>
+</div>
+
+<p>The reservoirs are true thermo-siphons. Consequently
+the water should be methodically circulated;
+in other words, the hottest water, flowing from the engine
+into the top of the first reservoir and having, for
+example, a temperature of 104 degrees F., is cooled off
+to 86 degrees F. and drops to the bottom of the reservoir,
+thence to be driven, at a temperature sensibly
+<!--106.png--><span class='pagenum'><a name="Page_106" id="Page_106">[106]</a></span>
+equal to 86 degrees F., to the second reservoir, where a
+further cooling of 18 degrees F. takes place. In passing
+on to the following reservoirs the temperature is
+still further lowered, until the water finally reaches its
+minimum temperature, after which it flows back to the
+engine-cylinder.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_064.jpg" width="600" height="447" alt="Fig. 64." title="" />
+<span class="caption"><span class='smcap'>Fig. 64.</span>&mdash;Circulating pump with by-pass.</span>
+</div>
+
+<p>In order to effect this cooling, the reservoirs can be
+connected in several ways. The most common method,
+as shown in Fig. 63, consists in connecting the reservoirs
+by oblique pipes. This is open to criticism, however,
+since leakage occurs, caused by the employment
+of elbows which retard the circulation. A less cumbrous
+and more efficient method of connection consists
+in joining the reservoirs by a single pipe at the top, as
+shown in Fig. 61; but care must be taken to extend this
+pipe at the point of its entrance into the adjoining
+reservoir by means of a downwardly projecting extension,
+or to fit its discharge-end with a box, closed by a
+single partition, open at the bottom.
+<!--107.png--><span class='pagenum'><a name="Page_107" id="Page_107">[107]</a></span></p>
+
+<p>In order to prevent incrustation of the water-jacket
+surrounding the cylinder, a pound of soda per 17 cubic
+feet of the reservoir capacity is monthly introduced,
+and the jacket flushed weekly by a cock conveniently
+mounted near the cylinder (Fig. 59). The jacket is
+thus purged of calcareous sediments, which are prevented
+by the soda from adhering to the metal. The
+flushing-cock mentioned also serves to drain the water-jacket
+of the cylinder in case of intense or persistent
+cold, which would certainly freeze the water in the
+jacket, thereby cracking the cylinder or the exposed
+pipes.</p>
+
+<p>In order to regulate the circulation of the water in
+accordance with the work performed by the engine, a
+cock should be fitted to the water supply pipe at a convenient
+place.</p>
+
+<p>In engines of large size, driven at full load for long
+periods, cooling by natural circulation is often inadequate.
+In such cases, circulation is quickened by a
+small rotary or reciprocating pump, driven from the
+engine itself and fitted with a by-pass provided with a
+cock. This arrangement permits the renewal of the
+natural thermo-siphon circulation in case of accident
+to the pump (Fig. 64).</p>
+
+<div class="figcenter" style="width: 597px;">
+<img src="images/fig_065.jpg" width="597" height="600" alt="Fig. 65." title="" />
+<span class="caption"><span class='smcap'>Fig. 65.</span>&mdash;Water-cooler in which tree branches
+are employed.</span>
+</div>
+
+<p><b>Coolers.&mdash;</b>The arrangement which is illustrated in
+Fig. 65, and which has the merit of simplicity, will be
+found of service in cooling the water. It comprises a
+tank <i>B</i> surmounted by a set of trays <i>E</i>, formed of frames
+to which iron rods are secured, spaced 1 to 2 feet apart,
+so as to form superimposed series separated by 1<sup>1</sup>&frasl;<sub>2</sub> to
+<!--108.png--><span class='pagenum'><a name="Page_108" id="Page_108">[108]</a></span>
+2<sup>1</sup>&frasl;<sub>3</sub> feet. On these trays bundles of tree branches are
+placed. The cold water at the bottom of the tank is
+forced by the pump <i>P</i>i into the water-jacket, from
+which it emerges hot, and flows through the pipe <i>T</i>,
+which ends in a sprinkler <i>G</i>, formed of communicating
+tubes and perforated with a sufficient number of
+holes to enable the water to fall upon the trays in many
+drops. Thus finely divided, the water falls from one
+tray to another, retarded as it descends by the bundles
+<!--109.png--><span class='pagenum'><a name="Page_109" id="Page_109">[109]</a></span>
+of tree branches. It finally reaches the tank in a very
+cold condition and is then ready to be pumped to the
+engine. Birch branches are to be preferred on account
+of their tenuity.</p>
+
+<p>Great care should be taken to cover the tank with
+a sheet-metal closure in order to prevent twigs and
+foreign bodies from entering and from being drawn
+into the pump.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_066.jpg" width="600" height="548" alt="Fig. 66." title="" />
+<span class="caption"><span class='smcap'>Fig. 66.</span>&mdash;Fan-cooler.</span>
+</div>
+
+<p>In the following table the dimensions of an operative
+apparatus of this kind are given,&mdash;an apparatus, moreover,
+that may be constructed of wood or of iron:&mdash;</p>
+
+<table style="text-align: center;" border="1"
+       cellpadding="4" cellspacing="0" summary="fancooler">
+<thead>
+ <tr>
+  <th scope="col">Horse-power.</th>
+    <th scope="col">Volume in cubic ft.</th>
+    <th scope="col">Tank Base.</th>
+    <th scope="col">Tank Height.</th>
+    <th scope="col">Height of tray-base.</th>
+    <th scope="col">Pump&mdash;Capacity in gals. per min.
+  </th>
+ </tr>
+</thead>
+ <tr><td>30</td>
+  <td> 105</td><td> 4.9' x 4.9'</td><td> 4.4'</td>
+  <td> 6.6'</td><td> 16.71</td>
+ </tr>
+ <tr><td>40</td>
+  <td> 154</td><td> 5.2' x 5.2'</td><td> 5.6'</td>
+  <td> 7.4'</td><td> 18.69</td>
+ </tr>
+ <tr><td>50</td>
+  <td> 190</td><td> 5.7' x 5.7'</td><td> 6.4'</td>
+  <td> 8.1'</td><td> 21.99</td>
+ </tr>
+ <tr><td>75</td>
+  <td> 350</td><td> 6.6' x 6.6'</td><td> 8.1'</td>
+  <td> 9.1'</td><td> 35.18</td>
+ </tr>
+ <tr><td>100</td>
+  <td> 490</td><td> 7.4' x 7.4'</td><td> 9.1'</td>
+  <td> 9.1'</td><td> 43.98</td>
+ </tr>
+</table>
+
+<!--110.png--><p><span class='pagenum'>110</span></p>
+
+<p>In order that the water may not drop to one side, the
+base of the apparatus should be made 10 to 12 inches
+less in width than the tank.</p>
+
+<p>The size of these apparatus may be considerably reduced
+by constructing them in the form of closed chests,
+into the bottom of which air maybe injected by means
+of fans in order to accelerate cooling (Fig. 66).</p>
+
+<hr class="ChapterTopRule" />
+<!--111.png--><p><span class='pagenum'><a name="Page_111" id="Page_111">[111]</a></span></p>
+
+<h2><a name="CHAPTER_VI" id="CHAPTER_VI"></a>CHAPTER VI</h2>
+
+<div class="c3">LUBRICATION</div>
+
+<p>Lubrication is a subject that should be studied by
+every gas-engine user. So far as the piston is concerned
+it is a matter of the utmost importance. The
+piston does its work under very peculiar conditions.
+It is driven at great linear velocities; and it is, moreover,
+subjected to high temperatures which have nothing
+in common with good lubrication if care be not
+exercised.</p>
+
+<p>The piston is the essential, vital element of an engine.
+Upon its freedom from leakage depends the
+maintenance of a proper compression, and, consequently,
+the production of power and economical consumption.
+As it travels forward and as it recedes from
+the explosion-chamber, it uncovers more and more of
+the frictional surface constituting the interior wall of
+the cylinder. This surface, as a result, is regularly
+brought into contact with the ignited, expanding gases
+after each explosion. For this reason the oil which
+covers the wall is constantly subjected to high temperatures,
+by which it is likely to be volatilized and burned.
+Therefore, the first condition to be fulfilled in properly
+lubricating the piston is a constant and regular supply
+of oil.
+<!--112.png--><span class='pagenum'><a name="Page_112" id="Page_112">[112]</a></span></p>
+
+<p><b>Quality of Oils.&mdash;</b>For cylinder lubrication only the
+very best oils should be used; perfect lubrication is of
+such importance that cost should not be considered.
+Besides, the surplus oil which is usually caught in the
+drip-pan is by no means lost. After having been filtered
+it can be used for lubricating the bearings of the
+crank, the cam-shaft, and like parts.</p>
+
+<p>Cylinder-oil should be exceedingly pure, free from
+acids, and composed of hydrocarbons that leave no residue
+after combustion. Only mineral oils, therefore,
+are suitable for the purpose. Those oils should be
+selected which, with a maximum of viscosity, are
+capable of withstanding great heat without volatilizing
+or burning. The point at which a good cylinder-oil
+ignites should not be lower than 535 degrees F.</p>
+
+<p>Whether an oil possesses this essential quality is
+easily enough ascertained in practice without resorting
+to laboratory tests. All that is necessary is to heat
+the oil in a metal vessel or a porcelain dish. In order
+that the temperature may be uniform the vessel is
+shielded from the direct flame by interposing a piece
+of sheet metal or a layer of dry sand. As soon as gases
+begin to arise a lighted match is held over the oil.
+When the gases are ignited the thermometer reading is
+taken, the instrument being immersed in the oil. The
+temperature recorded is that corresponding with the
+point of ignition.</p>
+
+<p>For cylinder lubrication American mineral oil is
+preferable to Russian oil. The specific gravity should
+lie somewhere between .886 and .889 at 70 degrees F.
+<!--113.png--><span class='pagenum'><a name="Page_113" id="Page_113">[113]</a></span>
+Oil of this quality begins to evaporate at about 365
+degrees F. Ignition occurs at 535 degrees F. The
+point of complete combustibility lies between 625 and
+645 degrees F. Oil of this quality solidifies at 39 or
+41 degrees F. Its color is a reddish yellow with a
+greenish fluorescence. Compared with water its degree
+of viscosity lies between 11.5 and 12.5 at a temperature
+of 140 degrees F.</p>
+
+<p>Before lubricating other parts of the engine with
+oil that has been used for the piston, heavy particles
+and foreign matter, such as dust, bearing incrustations,
+and the like, should be filtered out. The piston-pivot
+and the connecting-rod head are preferably
+lubricated with fresh oil, because their constant movement
+renders inspection difficult and the control of
+lubrication irksome. A good, industrial mineral oil
+of usual market quality will be found satisfactory.
+In order to bring home the importance of employing
+good cylinder-oil and of proper lubrication the
+author can only state that in his personal experience he
+has frequently detected losses varying from 10 to 15
+per cent. in the power developed by engines poorly
+lubricated.</p>
+
+<p><b>Types of Lubricators.&mdash;</b>Among the more common
+apparatus employed for automatically lubricating the
+cylinder, the author mentions an English oiler of the
+type pictured in Fig. 67 which is driven simply by
+a belt from the intermediary shaft, and which rotates
+the pulley <i>P</i> secured on the shaft <i>a</i> of the apparatus,
+at a very slow speed. The shaft <i>a</i> is provided at its
+<!--114.png--><span class='pagenum'><a name="Page_114" id="Page_114">[114]</a></span>
+end with a small crank, from which a small iron arm
+<i>f</i> is suspended, which arm dips in the oil contained in
+the cup <i>G</i> of the oiler. When the shaft <i>a</i> is turned this
+arm, as it sweeps through the oil-bath, collects a certain
+quantity of oil which it deposits on the collector
+<i>b</i>. From this spindle the oil passes through an outlet-pipe
+opening into the bottom of the oiler, and
+thence to the cylinder. The entire apparatus is closed
+by a cover <i>D</i> which can be easily removed in order to
+ascertain the quantity of oil still remaining in the
+apparatus. Many other systems are utilized which,
+like the one that has been described, enable the feed to
+be controlled. Often small force-pumps are employed
+as cylinder-lubricators. Whatever may be the type
+selected, preference should be given to that in which
+the feed is visible (Fig. 68).</p>
+
+<div class="figcenter" style="width: 400px;">
+<img src="images/fig_067.jpg" width="400" height="380" alt="Fig. 67." title="" />
+<span class="caption"><span class='smcap'>Fig. 67.</span>&mdash;An automatic English oiler.</span>
+</div>
+
+<p>If the oil be fed under pressure the cylinder is more
+constantly lubricated. Pressure-lubricators are nowadays
+widely used on large engines. It is advisable to
+<!--115.png--><span class='pagenum'><a name="Page_115" id="Page_115">[115]</a></span>
+add a little salt to the water contained in sight-feed
+lubricators so that the drop of oil is easily freed.</p>
+
+<p>These oil-pumps are provided with small check-valves
+at their outlets as well as at the inlets of cylinders.
+In order that pressure-lubricators may operate
+perfectly they should be regularly inspected and the
+check-valves ground from time to time.</p>
+
+<p>The lubrication of the crank-shaft and of the two
+connecting-rod heads should receive every attention.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_068.jpg" width="600" height="366" alt="Fig. 68." title="" />
+<span class="caption"><span class='smcap'>Fig. 68.</span>&mdash;Sight-feed lubricating-pump.</span>
+</div>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_069.jpg" width="600" height="483" alt="Fig. 69." title="" />
+<span class="caption"><span class='smcap'>Fig. 69.</span>&mdash;Method of oiling the piston and end of
+the connecting-rod.</span>
+</div>
+
+<p>Lubricating devices should be employed which,
+besides being efficient, do not necessitate the stopping
+of the engine in order to oil the bearings. The foot of
+the connecting-rod at the point where it is pivoted to
+the piston is generally lubricated with cylinder-oil
+which is supplied by a tube mounted in the proper
+place across the piston-wall (Fig. 69). This arrangement
+may be adequate enough for small engines;
+but it is not sufficiently sure for engines of considerable
+size. An independent lubricating system should be
+employed, lubrication being effected either by a
+<!--116.png--><span class='pagenum'><a name="Page_116" id="Page_116">[116]</a></span>
+splasher mounted in front of the cylinder or by a lubricator
+secured to the connecting-rod by which the pivot
+is lubricated through the medium of a small tube supplying
+special oil (Fig. 21). The head of the connecting-rod
+where it meets the crank, must also be
+carefully lubricated because of the important nature
+of the work which it must perform, and because of the
+shocks to which it is subjected at each explosion. For
+motors of high power the system which seems to give
+most satisfactory results is that illustrated in Fig. 70.
+The arrangement there shown consists of an annular
+vessel secured at one side of the crank and turning concentrically
+on its axis; the vessel being connected with a
+long tube extending into a channel formed in the crank
+and discharging at the surface of the crank-pin within
+the bearing at the head of the connecting-rod. An
+adjustable sight-feed lubricator conducts the oil along
+a pipe to the vessel. Turning with the shaft, the vessel
+<!--117.png--><span class='pagenum'><a name="Page_117" id="Page_117">[117]</a></span>
+retains the oil in the periphery so that the feed in
+the previously mentioned channel in the connecting-rod
+head, is constant.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_070.jpg" width="600" height="415" alt="Fig. 70." title="" />
+<span class="caption"><span class='smcap'>Fig. 70.</span>&mdash;Method of oiling the crank-shaft.</span>
+</div>
+
+<p>The main crank-shaft bearings are more easily lubricated.
+Among the systems commonly used with good
+results may be mentioned that shown in Fig. 71, in
+which the half section represents a small tube starting
+from the bearing and terminating in the interior of an
+oil recess or reservoir cast integrally with the bearing-cap.
+This reservoir is filled up to the level of the tube
+opening. A piece of cotton waste held on a small iron
+wire is inserted in the tube, part of the cotton being
+allowed to hang down in the reservoir. This cotton
+serves as a kind of siphon and feeds the bearing by
+capillary attraction with a constant quantity of oil, the
+supply being regulated by varying the thickness of the
+<!--118.png--><span class='pagenum'><a name="Page_118" id="Page_118">[118]</a></span>
+cotton. When the motor is stopped, the cotton should
+be removed in order that oil-feeding may not uselessly
+continue. Glass, sight-feed lubricators with
+stop-cocks, are very often used on crank-shafts. They
+are cleaner and much more easily regulated. Of all
+shaft-bearing lubricators, those which are most to be
+recommended are of the revolving-ring type (Fig.
+72). They presuppose, however, bearings of large
+size and a special arrangement of bushings which renders
+their application somewhat expensive. Furthermore,
+the revolving-ring system can hardly be used in
+connection with engines of less than 20 horse-power.
+Since the system is applied almost exclusively to
+dynamo-shafts, it need not here be described in detail.
+As its name indicates, it consists of a metal ring having
+a diameter larger than that part of the shaft from
+which it is suspended and by which it is rotated. The
+lower part of the ring is immersed in an oil bath so
+<!--119.png--><span class='pagenum'><a name="Page_119" id="Page_119">[119]</a></span>
+that a certain quantity of lubricant is continually transferred
+to the shaft.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_071.jpg" width="600" height="494" alt="Fig. 71." title="" />
+<span class="caption"><span class='smcap'>Fig. 71.</span>&mdash;Cotton-waste lubricator.</span>
+</div>
+
+<p>The revolving ring bearing should be fitted with a
+drain-cock and a glass tube in order to control the
+level of the oil in the bearing.</p>
+
+<p>Many manufacturers have adopted lubricating devices
+for valve-stems, and especially for exhaust-valves.
+The system adopted consists of a small tube curved in
+any convenient direction and discharging in the stem-guide.
+The free end is provided with a plug. A few
+drops of petroleum are introduced once or twice a day.</p>
+
+<div class="figcenter" style="width: 485px;">
+<img src="images/fig_072.jpg" width="485" height="600" alt="Fig. 72." title="" />
+<span class="caption"><span class='smcap'>Fig. 72.</span>&mdash;Ring type of bearing oiler.</span>
+</div>
+
+<p>The lubrication of an engine entails certain difficulties
+which are easily overcome. One of these is the
+<!--120.png--><span class='pagenum'><a name="Page_120" id="Page_120">[120]</a></span>
+splashing of oil by the connecting-rod head. In order
+that this splashed oil may be collected in the base
+of the engine a suitably curved sheet-metal guard is
+mounted over the crank. A more serious difficulty
+is presented when the oil from a crank-bearing finds
+its way to the hub of the fly-wheel, whence it is driven
+by the centrifugal force to the rim. The oil is not only
+splashed against the walls of the engine-room, but it
+also destroys the adhesion of the belt if the fly-wheel
+be employed as a pulley. In order to overcome this
+objection the oil is prevented from spreading along the
+shaft by means of a circular guard (Fig. 73) mounted
+on that portion of the shaft toward the interior of the
+bearing.</p>
+
+<div class="figcenter" style="width: 500px;">
+<img src="images/fig_073.jpg" width="500" height="470" alt="Fig. 73." title="" />
+<span class="caption"><span class='smcap'>Fig. 73.</span>&mdash;Shaft with oil-guard.</span>
+</div>
+
+<p>The problem of lubrication is of particular importance
+if the engine is driven for several days at
+a time without a stop. This happens in the case of
+mill and shop engines. Lubricators of large volume
+or lubricators which can be readily filled without stopping
+the engine should be employed.</p>
+
+<hr class="ChapterTopRule" />
+<!--121.png--><p><span class='pagenum'><a name="Page_121" id="Page_121">[121]</a></span></p>
+<h2><a name="CHAPTER_VII" id="CHAPTER_VII"></a>CHAPTER VII</h2>
+
+<div class="c3">THE CONDITIONS OF PERFECT OPERATION</div>
+
+<p><b>General Care.&mdash;</b>Gas-engines, as well as most machines
+in general, should be kept in perfect condition.
+Cleanliness, even in the case of parts of secondary importance,
+is indispensable. Unpainted and polished
+surfaces such as the shaft of the engine, the distributing
+cam-shafts, the levers, the connecting-rod and the
+like, should be kept in a condition equal to that when
+they were new. The absence of all traces of rust or
+corrosion in these parts affords sufficient evidence of
+the care taken of the invisible members such as the
+piston, the valves, ignition devices, and the like.</p>
+
+<p><b>Lubrication.&mdash;</b>The rubbing surfaces of a gas-engine
+should be regularly and perfectly lubricated. The
+absence of lost motion and backlash in the bearings,
+guides, and joints is of particular importance not only
+because of its influence on steady and silent running,
+but also on the power developed and on the consumption.
+As we have already seen in the chapter on lubrication,
+a special quality of oil should be employed for
+the lubrication of the cylinder. The feed of the lubricator
+supplying this most vital part of the engine is so
+regulated that it meets the actual requirements with
+the utmost nicety possible. In a subsequent chapter,
+<!--122.png--><span class='pagenum'><a name="Page_122" id="Page_122">[122]</a></span>
+in which faulty operation will be discussed, it will be
+shown how too much and too little oil may cause serious
+trouble.</p>
+
+<p><b>Tightness of the Cylinder.&mdash;</b>The amount of power
+developed depends principally on the degree of compression
+to which the explosive mixture is subjected.
+The economical operation of the engine depends in
+general upon perfect compression. It is, therefore,
+necessary to keep those parts in good order upon which
+the tightness of the cylinder depends. These parts are
+the piston, the valves, and their joints, and the ignition
+devices whether they be of the hot-tube or electrical
+variety. In order to prevent leakage at the piston,
+the rings should be protected from all wear. It
+is of the utmost importance that the surfaces both of
+the piston and of the cylinder, be highly polished so
+that binding cannot occur. In cleansing the cylinder,
+emery paper or abrasive powder should not be employed;
+for the slightest particle of abrasive between
+the surfaces in contact will surely cause leakage. The
+oil and dirt, which is turned black by friction and
+which may adhere to the piston rings, should be
+washed away with petroleum. Similarly the other
+parts of the cylinder should be cleaned to which burnt
+oil tends to adhere.</p>
+
+<p><b>Valve-Regrinding.&mdash;</b>The valves should be regularly
+ground. Even in special cases where they may
+show no trace of rapid wear they should be removed
+at least every month. In order to avoid any accident,
+care should be taken in adjusting the valves after the
+<!--123.png--><span class='pagenum'><a name="Page_123" id="Page_123">[123]</a></span>
+cap has been unbolted not to introduce a candle or a
+lighted match either in the valve-chambers or in the
+cylinder, without first closing the gas-cock. Furthermore,
+a few turns should be given to the engine, in
+order to drive out any explosive mixture that may still
+remain in the cylinder or the connected passages. The
+exhaust-valve, by reason of the high temperature to
+which the disk and the seat are subjected, should receive
+special attention. The valve should be ground
+on its seat every two or three months at least, depending
+upon the load of the engine.</p>
+
+<p><b>Bearings and Crosshead.&mdash;</b>The bushings of the engine
+shaft should always be held tightly in place. The
+looseness to which they are liable, particularly in gas-engines
+on account of the sharp explosions, tends to
+unscrew the nuts and to hasten the wear of the brass,
+which is the result of frequent tightening. The slightest
+play in the bearings of the engine-shaft as well as
+in the bearings of connecting-rods increases the sound
+that engines naturally produce.</p>
+
+<p><b>Governor.&mdash;</b>The governor should receive careful attention
+so far as its cleanliness is concerned; for if its
+operation is not easy it is apt to become "lazy" and
+to lose its sensitiveness. If the governor be of the ball
+type, or of the conical pendulum type operated by
+centrifugal force, it is well to lubricate each joint without
+excess of oil. In order to prevent the accumulation
+and the solidification of oil, the governor should
+be lubricated from time to time with petroleum. If
+the governor is actuated by inertia, which is the case
+<!--124.png--><span class='pagenum'><a name="Page_124" id="Page_124">[124]</a></span>
+in most engines of the hit-and-miss variety, it needs
+less care; still, it is advisable to keep the contact at
+which the thrust takes place well oiled.</p>
+
+<p>The operation of any of these governors is usually
+controlled by the tension of a spring, or by a counterweight.
+In order to increase the speed of the engine,
+or in other words, to increase the number of admissions
+of gas in a given time, all that is usually necessary is
+to tighten up the spring, or to change the position of
+the counterweight. It should be possible to effect
+this adjustment while the engine is running in such a
+manner that the speed can be easily changed.</p>
+
+<p><b>Joints.&mdash;</b>In most well-built engines the caps of the
+valve-chests and other removable parts are secured
+"metal on metal" without interposing special joints.
+In other words, the surfaces are themselves sufficiently
+cohesive to insure perfect tightness. In engines which
+are not of this class, asbestos joints are very frequently
+employed, particularly at the exhaust-valve cap and
+the suction-valve.</p>
+
+<p>In some engines, where for any reason it is necessary
+frequently to detach the caps, certain precautions should
+be taken to protect the joints so that they may not be
+exposed to deterioration whenever they are removed.
+For this purpose, they are first immersed in water in
+order to be softened, then dried and washed with olive
+or linseed oil on the side upon which they rest in the
+engine. On the cap side they are dusted with talcum
+or with graphite. Treated in this manner, the joint
+will adhere on one side and will be easily released on
+<!--125.png--><span class='pagenum'><a name="Page_125" id="Page_125">[125]</a></span>
+the other. Joints that are liable to come in contact
+with the gases in the explosion-chamber should be free
+from all projections toward the interior of the cylinder;
+for during compression these uncooled projections
+may become incandescent and may thus cause premature
+ignition. As a general rule when the cap is
+placed in position the joint should be retightened after
+a certain time, when the surfaces have become sufficiently
+heated. In order to tighten the joints the bolts
+and nuts should not be oiled; otherwise the removal of
+the cap becomes difficult.</p>
+
+<p><b>Water Circulation.&mdash;</b>In a previous chapter, the importance
+of the water circulation and the necessity of
+keeping the cylinder-jacket hot, have been sufficiently
+dwelt upon. As the cylinder tends to become hotter
+with an increase in the load, because of the greater frequency
+of explosions, it is advisable to regulate the
+flow of the water in order to prevent its becoming more
+than sufficient in quantity when the engine is lightly
+loaded; for under these conditions the cylinder will be
+cold and the explosive mixture will be badly utilized.
+A suitable temperature of 140 to 158 degrees F. is
+easily maintained by adjusting the circulation of the
+water. This can be accomplished by providing the
+water-inlet pipe leading to the cylinder with a cock
+which can be opened more or less, as may be necessary.
+The temperature of 140 to 158 degrees F., which has
+been mentioned, may, at first blush, seem rather high
+because it would be impossible to keep the hand on the
+outlet-pipe. The cylinder, however, will not become
+<!--126.png--><span class='pagenum'><a name="Page_126" id="Page_126">[126]</a></span>
+overheated so long as it is possible to hold the hand
+beneath the jacket near the water-inlet. This relates
+only to engines having a compression of 50 to 100 lbs.
+per square inch. For engines of higher compression,
+a lower running temperature will be safer. On this
+matter the instructions of the engine maker should be
+carried out.</p>
+
+<p><b>Adjustment.&mdash;</b>Gas-engines, at least those which are
+built by trustworthy firms, are always put to the brake
+test before they are sent from the shops, and are adjusted
+to meet the requirements of maximum efficiency.
+But since the nature and quality of gas necessarily
+vary with each city, it is evident that an engine
+adjusted to develop a certain horse-power with a gas
+of a certain richness, may not fulfil all expectations
+if it is fed with a gas less rich, less pure, hotter, and
+the like. The altitude also has some influence on the
+efficiency of the engine. As it increases, the density of
+the mixture diminishes; that is to say, for the same volume
+the engine is using a smaller amount. From this
+it follows that a gas-engine ought to be adjusted as a
+general rule on the spot where it is to be used.</p>
+
+<p>The fulfilment of this condition is particularly important
+in the case of explosion-engines, because an
+advancement or retardation of only one-half a second
+in igniting the explosive mixture will cause a considerable
+loss in useful work. From this it would follow
+that gas-engines should be periodically inspected in
+order that they may operate with the highest efficiency
+and economy. As in the case of steam-engines, it is
+<!--127.png--><span class='pagenum'><a name="Page_127" id="Page_127">[127]</a></span>
+advisable to take indicator records which afford conclusive
+evidence of the perturbations to which every
+engine is subject after having run for some time.</p>
+
+<p>Most gas-engine users either have no indicating instruments
+at their disposal or else are not sufficiently
+versed in their employment and the interpretation of
+their records to study perturbations by their means.
+For this reason the advice of experts should be sought,&mdash;men
+who understand the meaning of the diagrams
+taken and who are able by their means to effect a considerable
+saving in gas.</p>
+
+<hr class="ChapterTopRule" />
+<!--128.png--><p><span class='pagenum'><a name="Page_128" id="Page_128">[128]</a></span></p>
+<h2><a name="CHAPTER_VIII" id="CHAPTER_VIII"></a>CHAPTER VIII</h2>
+
+<div class="c3">HOW TO START AN ENGINE&mdash;PRELIMINARY PRECAUTIONS</div>
+
+<p>The first step which is taken in starting an engine
+driven by street-gas is, naturally, the opening of the
+meter-cock and the valves between the meter and
+the engine. When the gas has reached the engine, the
+rubber bags will swell up and the anti-pulsator diaphragm
+will be forced out. The drain-cock of the gas-pipe
+is then opened. In order to ascertain whether
+the flow of gas is pure, a match is applied to the outlet
+of the cock. The flame is allowed to burn until it
+changes from its original blue color to a brilliant
+yellow.</p>
+
+<p>If the hot-tube system of ignition be employed, the
+Bunsen burner is ignited, care being taken that the
+flame emerging from the tube is blue in color. If
+necessary the admission of air to the burner is regulated
+by the usual adjusting-sleeve. A white or smoky
+flame indicates an insufficient supply of air to the
+burner. A characteristic sooty odor is still other evidence
+of the same fact. Sometimes a white flame may
+be produced by the ignition of the gas at the opening
+of the adjusting-sleeve. A blue or greenish flame is
+that which has the highest temperature and is the one
+<!--129.png--><span class='pagenum'><a name="Page_129" id="Page_129">[129]</a></span>
+which should, therefore, be obtained. About five or
+ten minutes are required to heat up the tube, owing to
+the material of which it is made. When the proper
+temperature has been attained the tube becomes a dazzling
+cherry red in color. While the tube is being
+heated up, it is well to determine whether the engine
+is properly lubricated and all the cups and oil reservoirs
+are duly filled up. The cotton waste of the
+lubricators should be properly immersed, and the drip
+lubricators examined to determine whether they are
+supplying their normal quantity of oil.</p>
+
+<p>The regulating-levers of the valves should be operated
+in order to ascertain whether the valves drop upon
+their seats as they should. The stem of the exhaust-valve
+should be lubricated with a few drops of petroleum.</p>
+
+<p>If the ignition system employed be of the electric
+type, with batteries and coils, tests should be made to
+determine whether the current passes at the proper
+time on completing the circuit with the contact
+mounted on the intermediary shaft. This contact
+should produce the characteristic hum caused by the
+operation of the coil.</p>
+
+<p>If a magneto be used in connection with the ignition
+apparatus, its inspection need not be undertaken
+whenever the engine is started, because it is not so
+likely to be deranged. Still, it is advisable, as in the
+case of ignition by induction-coils, to set in position
+the device which retards the production of the spark.
+This precaution is necessary in order to avoid a premature
+<!--130.png--><span class='pagenum'><a name="Page_130" id="Page_130">[130]</a></span>
+explosion, liable to cause a sharp backward revolution
+of the fly-wheel.</p>
+
+<p>After the ignition apparatus and the lubricators have
+been thus inspected, the engine is adjusted with the
+piston at the starting position, which is generally indicated
+by a mark on the cam-shaft. The starting position
+corresponds with the explosion cycle and is generally
+at an angle of 40 to 60 degrees formed by the
+crank above the horizontal and toward the rear of the
+engine. The gas-cock is opened to the proper mark,
+usually shown on a small dial. If there be no mark,
+the cock is slowly opened in order that no premature
+explosion may be caused by an excess of gas.</p>
+
+<p>The steps outlined in the foregoing are those which
+must be taken with all motors. Each system, however,
+necessitates peculiar precautions, which are
+usually given in detailed directions furnished by the
+builder.</p>
+
+<p>As a general rule the engines are provided on their
+intermediary shafts with a "relief" or "half-compression"
+cam. By means of this cam the fly-wheel
+can be turned several times without the necessity of
+overcoming the resistance due to complete compression.
+Care should be taken, however, not to release
+the cam until the engine has reached a speed sufficient
+to overcome this resistance.</p>
+
+<p>Engines of considerable size are commonly provided
+with an automatic starting appliance. In order to
+manipulate the parts of which this appliance is composed,
+the directions furnished by the manufacturer
+<!--131.png--><span class='pagenum'><a name="Page_131" id="Page_131">[131]</a></span>
+must be followed. Particularly is this true of automatic
+starters comprising a hand-pump by means of
+which an explosive mixture is compressed,&mdash;true because
+in the interests of safety great care must be taken.</p>
+
+<p>The tightness and free operation of the valves or
+clacks which are intended to prevent back firing
+toward the pump should be made the subject of careful
+investigation. Otherwise, the piston of the pump
+is likely to receive a sudden shock when back firing occurs.</p>
+
+<p>When the engine has been idle for several days, it
+is advisable, before starting, to give it several turns
+(without gas) in order to be sure that all its parts
+operate normally. The same precaution should be
+taken in starting an engine, if a first attempt has failed,
+in order to evacuate imperfect mixtures that may be
+left in the cylinder. Before this test is made, the gas-cock
+should, of course, be closed in order to prevent
+an untimely explosion. It is advisable in starting an
+engine not to bend the body over the ignition-tube,
+because the tube is likely to break and to scatter dangerous
+fragments.</p>
+
+<p>Under no condition whatever should the fly-wheel
+be turned by placing the foot upon the spokes. All
+that should be done is to set it in motion by applying
+the hand to the rim.</p>
+
+<p><b>Care During Operation.&mdash;</b>When the engine has acquired
+its normal speed, the governor should be looked
+after in order that its free operation may be assured
+and that all possibility of racing may be prevented.
+<!--132.png--><span class='pagenum'><a name="Page_132" id="Page_132">[132]</a></span>
+After the engine has been running normally for a time,
+the cocks of the water circulation system should be
+manipulated in order to adjust the supply of water to
+the work performed by the engine. In other words
+the cylinder should be kept hot, but not burning, as
+previously explained in the paragraph in which the
+water-jacket is discussed. The maintenance of a suitable
+temperature is extremely important so far as
+economy is concerned. All the bearings should be inspected
+in order that hot boxes may be obviated.</p>
+
+<p><b>Stopping the Engine.&mdash;</b>The steps to be taken in
+stopping the engine are the following:</p>
+
+<p>1. Stopping the various machines driven by the engine,&mdash;a
+practice which is followed in the case of all
+motors;</p>
+
+<p>2. Throwing out the driving-pulley of the engine
+itself, if there be one;</p>
+
+<p>3. Closing the cock between the meter and the gas-bags
+in order to prevent the escape of gas and the useless
+stretching of the rubber of the bags or of the anti-pulsating
+devices;</p>
+
+<p>4. Actuating the half-compression or relief cam as
+the motor slows down, in order to prevent the recoil
+due to the compression;</p>
+
+<p>5. Closing the gas-admission cock;</p>
+
+<p>6. Shutting off the supply of oil of free flowing
+lubricators, and lifting out the cotton from the others.</p>
+
+<p>If the engine be used to drive a dynamo, particularly
+a dynamo provided with metal brushes, the precaution
+should be taken of lifting the brushes before the engine
+<!--133.png--><span class='pagenum'><a name="Page_133" id="Page_133">[133]</a></span>
+is stopped in order to prevent their injury by a
+return movement of the armature-shaft;</p>
+
+<p>7. Shutting off the cooling-water cock if running
+water is used.</p>
+
+<p>If the engine is exposed to great cold, the freezing
+of the water in the jacket is prevented while the engine
+is at rest, either by draining the jacket entirely, or by
+arranging a gas jet or a burner beneath the cylinder
+for the purpose of causing the water to circulate. If
+such a burner be used the cocks of the water supply
+pipe should, of course, be left open.
+</p>
+
+<hr class="ChapterTopRule" />
+<!--134.png--><p><span class='pagenum'><a name="Page_134" id="Page_134">[134]</a></span></p>
+<h2><a name="CHAPTER_IX" id="CHAPTER_IX"></a>CHAPTER IX</h2>
+
+<div class="c3">PERTURBATIONS IN THE OPERATION OF ENGINES AND
+THEIR REMEDY</div>
+
+<p>In this chapter will be discussed certain perturbations
+which affect the operations of gas-engines to a
+more marked degree than lack of care in their construction.
+In previous chapters defects in operation
+due to various causes have been dwelt upon, such as
+objectionable methods in the construction of an engine,
+ill-advised combination of parts, defects of installation,
+and the like; and an attempt has been made to determine
+in each case the conditions which must be fulfilled
+by the engine in order to secure efficiency and
+economy at a normal load.</p>
+
+<p><b>Difficulties in Starting.&mdash;</b>The preliminary precautions
+to be taken in starting an engine having been indicated,
+it is to be assumed that the advice given has
+been followed. Nevertheless various causes may prevent
+the starting of the engine.</p>
+
+<p><b>Faulty Compression.&mdash;</b>Defective compression, as a
+general rule, prevents the ignition of the explosive
+mixture. Whether or not the compression be imperfect
+can be ascertained by moving the piston back to
+the period corresponding with compression, in other
+words, that position in which all valves are closed.
+<!--135.png--><span class='pagenum'><a name="Page_135" id="Page_135">[135]</a></span>
+If no resistance be encountered, it is evident that the
+air or the gaseous mixture is escaping from the cylinder
+by way of the admission-valve, the exhaust-valve,
+or the piston. The valves, ordinarily seated by springs,
+may remain open because their stems have become
+bound, or because some obstruction has dropped in
+between the disk and the seat. In a worn-out or badly
+kept engine the valves are likely to leak. If that be
+the case grinding is the only remedy. If a valve be
+clogged, which becomes sufficiently evident by manipulating
+the controlling levers, it is necessary simply to
+clean the stem and its guides in order to remove the
+caked oil which accumulates in time. If the engine be
+new, the binding of the valve-stems is often caused by
+insufficient play between the stems and their guides.
+Should this prove to be the case, the defect is remedied
+by rubbing the frictional surface of the stem with fine
+emery paper and by lubricating it with cylinder-oil.
+The exhaust-valve, however, should be lubricated only
+with petroleum.</p>
+
+<p>It is not unlikely that the exhaust-valve may leak
+for two other reasons. In the first place, the tension of
+the spring which serves to return the valve may have
+lessened and may be insufficient to prevent the valve
+from being unseated during suction. Again, the screw
+or roller serving as a contact between the lever and the
+valve-stem, may not have sufficient play, so that the
+lengthening of the stem on account of its expansion
+may prevent the valve from falling back on its seat.
+The first-mentioned defect is remedied by renewing
+<!--136.png--><span class='pagenum'><a name="Page_136" id="Page_136">[136]</a></span>
+the spring, or by the provision of an additional spring
+or of a counterweight in order to prevent the stoppage
+of the motor. The second defect can be remedied by
+regulating the contact.</p>
+
+<p>Leakage past the piston may be caused by the breaking
+of one or more rings, by wear or binding of the
+rings, or by wear or binding of the cylinder. The
+whistling caused by the air or the mixture as it passes
+back proves the existence of this fault.</p>
+
+<p><b>Presence of Water in the Cylinder.&mdash;</b>It may sometimes
+happen that water may find its way into the cylinder
+with the gas by reason of the bad arrangement
+of the piping. It may also happen that water may
+enter the cylinder through the water-jacket joint.
+Again, the presence of water in the cylinder may be
+due to condensation of the steam formed by the chemical
+union of the hydrogen of the gas and the oxygen of
+the air, which condensation is caused by the cool walls
+of the cylinder. The water may sometimes accumulate
+in the exhaust pipe and box, when they have been improperly
+drained, and may thus return to the cylinder.
+Whatever may be its cause, however, the presence of
+water in the cylinder impedes the starting of the engine,
+because the gases resulting from the explosion are
+almost spontaneously chilled, thereby diminishing the
+working pressure.</p>
+
+<p>If electric ignition be employed, drops of water may
+be deposited between the contacts, thereby causing
+short circuits which prevent the passing of the spark.</p>
+
+<p>If there be no drain-cock on the cylinder, the difficulty
+<!--137.png--><span class='pagenum'><a name="Page_137" id="Page_137">[137]</a></span>
+of starting the engine can be overcome only by
+ceaseless attempts to set it in motion. The leaky condition
+of a joint as well as the presence of a particle of
+gravel in the cylinder-casting, through which the water
+can pass from the jacket, is attested by the bubbling up
+of gas in the water-tank at the opening of the supply
+tube. These bubbles are caused by the passage of the
+gas through the jacket after the explosion. If such
+bubbles be detected, the cylinder should be renewed
+or the defect remedied. In order to obviate any danger,
+the stop-cocks of the water-jacket, which have
+already been described in a previous chapter, should be
+closed while the engine is idle.</p>
+
+<p><b>Imperfect Ignition.&mdash;</b>The difficulties encountered in
+starting an engine, and caused by imperfect ignition,
+vary in their nature with the character of the ignition
+system employed, whether that system, for example,
+be of the electric, or of the incandescent or hot
+tube type. Frequently it happens that in starting an
+engine a hot tube may break. If the tube be of porcelain
+the accident may usually be traced to improper
+fitting or to the presence of water in the cylinder. If
+the tube be of metal, its breaking is caused usually by
+a weakening of the metal through long use&mdash;an accident
+that occurs more often in starting the engine than
+in normal operation, because the explosions at starting
+are more violent, owing to the tendency of the supply-pipes
+to admit an excess of gas at the beginning.</p>
+
+<p>A misfire arising from a faulty tube in starting may
+be caused by an obstruction or by leaks at the joints or
+<!--138.png--><span class='pagenum'><a name="Page_138" id="Page_138">[138]</a></span>
+in the body of the tube itself, thereby allowing a certain
+quantity of the mixture to escape before ignition. This
+defect in the tube is usually disclosed by a characteristic
+whistling sound.</p>
+
+<p>A tube may leak either at the bottom or at the top.
+In the first case, starting is very difficult, because the
+part of the mixture compressed toward the tube will
+escape through the opening before it reaches the incandescent
+zone. In the second case, ignition may be
+simply retarded to so marked an extent that a sufficient
+motive effect cannot be produced. An example of this
+retardation, artificially produced to facilitate the starting
+and to obviate premature explosions, is found in a
+system of ignition-tubes provided with a small cock
+or variable valve (Figs. 74 and 75).</p>
+
+<div class="figcenter" style="width: 425px;">
+<img src="images/fig_074.jpg" width="425" height="600" alt="Fig. 74." title="" />
+<span class="caption"><span class='smcap'>Fig. 74.</span></span>
+</div>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_075.jpg" width="600" height="575" alt="Fig. 75." title="" />
+<span class="caption"><span class='smcap'>Fig. 75.</span>&mdash;Ignition-tubes
+provided with needle valves to facilitate starting.</span>
+</div>
+
+<p>The mere enumeration of defects caused by leakage
+is sufficient to indicate the remedy to be adopted. It
+may be well to recall in this connection the important
+part played by the ignition-valve. If it be leaky, or if
+<!--139.png--><span class='pagenum'><a name="Page_139" id="Page_139">[139]</a></span>
+its free operation be impeded, starting will always be
+difficult.</p>
+
+<p><b>Electric Ignition by Battery or Magneto.&mdash;</b>If the
+electric ignition apparatus, whatever may be the
+method by which the spark is produced, be imperfect
+in operation, the first step to be taken is to ascertain
+whether the spark is produced at the proper time, in
+other words, slightly after the dead center in the particular
+position given to the admission device at starting.
+If a coil and a battery be employed, it is advisable
+to remove the plug and to place it with its armature
+upon a well-polished metal surface to produce an
+electrical contact, preventing, however, the contact of
+the binding post with this metallic surface. The same
+method of inspection is adopted with the make-and-break
+apparatus of an electric magneto. In both cases
+it should be ascertained whether or not there is any
+short-circuiting. The contacts should be cleaned with
+a little benzine if they are covered with oil or caked
+grease.</p>
+
+<p>If no spark is produced at the plug or at the make-and-break
+device it may be inferred that the wires are
+broken or that the generating apparatus is out of order.
+A careful examination will indicate what measures are
+to be taken to cure the defects.</p>
+
+<p><b>Premature Ignition.&mdash;</b>It has several times been
+stated that the moment of ignition of the gaseous mixture
+has a pronounced influence on the operation of
+gas-engines and upon their economy.</p>
+
+<p>Premature ignition takes place when there is a violent
+<!--140.png--><span class='pagenum'><a name="Page_140" id="Page_140">[140]</a></span>
+shock at the moment when the piston leaps from
+the rear dead center to the end of the compression
+stroke. The violent effects produced are all the more
+harmful because they tend to overheat the interior of
+the engine and thereby to increase in intensity.</p>
+
+<p>Premature ignition may be due to several causes.
+If a valveless hot tube be employed it may happen
+that the incandescent zone is too near the base. If
+the tube be provided with a valve, it very frequently
+happens that the valve leaks or that it opens too soon.
+In the case of electric ignition, the circuit may be
+completed before the proper time, because of faulty
+regulation. The suggestions made in the preceding
+chapters indicate the method of remedying these
+defects.</p>
+
+<p>Faulty ignition may have its origin not only in the
+method of ignition employed, but also in excessive heating
+of the internal parts of the engine, caused by continual
+overloading or by inadequate circulation of
+water.</p>
+
+<p>Passing to those cases of premature ignition of a
+special nature which are not due to any functional defect
+in the engine, but which are purely accidental in
+origin, such as the uncleanliness of the parts within the
+cylinder or the presence of some projecting part which
+becomes heated to incandescence during compression,
+it should first be stated that these ignitions, usually
+termed spontaneous, often occur well in advance of the
+end of the compression stroke. They are characterized
+by a more marked shock than that caused by ordinary
+<!--141.png--><span class='pagenum'><a name="Page_141" id="Page_141">[141]</a></span>
+premature ignition and usually result in bringing the
+engine to a complete stop in a very short time. These
+spontaneous explosions counteract to such an extent
+the impulse of the compression period, during which
+the piston is moving back, that they have a tendency
+to reverse the direction in which the engine is running.
+In such cases a careful inspection and a scrupulous
+cleaning of the cylinder and of the piston should be
+undertaken.</p>
+
+<p>The bottom of the piston is particularly likely to retain
+grease which has become caked, and which is
+likely to become heated to incandescence and spontaneously
+to ignite the explosive mixture.</p>
+
+<p><b>Untimely Detonations.&mdash;</b>The sound produced by
+the explosions of a normally operating engine can
+hardly be heard in the engine-room. Untimely detonations
+are produced either at the exhaust, or in the suction
+apparatus, near the engine itself. These detonations
+are noisier than they are dangerous; still, they
+afford evidence of some fault in the operation which
+should be remedied.</p>
+
+<p>Detonations produced at the exhaust are caused by
+the burning of a charge of the explosive mixture in the
+exhaust-pipe, which charge, for some reason, has not
+been ignited in the cylinder, and has been driven into
+the exhaust-pipe, where it catches fire on coming into
+contact with the incandescent gases discharged from
+the cylinder after the following explosion.</p>
+
+<p>Detonations produced in the suction apparatus of
+the engine, which apparatus is either arranged in the
+<!--142.png--><span class='pagenum'><a name="Page_142" id="Page_142">[142]</a></span>
+base itself or in a separate chest, are often noisier than
+the foregoing. They are caused by the accidental backward
+flowing of the explosive mixture, and by its ignition
+outside of the cylinder. The accident may be
+traced to three causes:</p>
+
+<p>1. The suction-valve of the mixture may not be tight
+and may leak during the period of compression, allowing
+a certain quantity of the mixture to pass into the
+suction-chest or into the frame. When the explosion
+takes place in the cylinder that part of the mixture
+which has passed back is ignited, as we have just seen,
+thereby producing a very loud deflagration. The obvious
+remedy consists in making the suction-valve tight
+by carefully grinding it.</p>
+
+<p>2. It may happen that at the end of the exhaust
+stroke incandescent particles may remain in the cylinder,
+which particles may consist of caked oil or may
+be retained by poorly cooled projections. The result is
+that the mixture is prematurely ignited during the suction
+period.</p>
+
+<p>3. The engine is so regulated, particularly in the
+case of English-built engines, as to effect what is technically
+called "scavenging" the products of combustion.
+In order to obtain this result, the mixture-valve
+is opened before the end of the exhaust stroke of the
+piston and the closing of the exhaust-valve. Owing to
+the inertia and the speed acquired by the products of
+combustion shot into the exhaust-pipe after explosion,
+a lowering of the pressure is produced in the cylinder
+toward the end of the stroke, causing the entrance of
+<!--143.png--><span class='pagenum'><a name="Page_143" id="Page_143">[143]</a></span>
+air by the open admission-valve and consequently
+effecting the scavenging of the burnt gases, part of
+which would otherwise remain in the cylinder. It is
+evident that if a charge of the mixture has not been
+normally exploded, either because its constituents have
+not been mingled in the proper proportion, or because
+the ignition apparatus has missed fire, this charge at the
+moment of exhausting will pass out of the cylinder
+without any acquired speed, and will flow back in part
+at the end of the exhaust stroke past the prematurely
+opened admission-valve, thereby lodging in the air suction
+apparatus. Despite the suction which takes place
+immediately following the re-entrance of the gas into
+the cylinder, a certain quantity of the mixture is still
+confined in the suction-pipe and its branches, where it
+will catch fire at the end of the exhaust stroke after the
+opening of the mixture-valve.</p>
+
+<p>In order to avoid these detonations it is necessary
+simply to see to it that the mixture is regularly ignited.
+This is accomplished by mixing the gas and air in
+proper proportions or by correcting the ignition time.</p>
+
+<p><b>Retarded Explosions.&mdash;</b>Retarded explosions considerably
+reduce the power which an engine should normally
+yield, and sensibly increase the consumption.
+They are due to three chief causes: (1), faulty ignition;
+(2), the poor quality of the mixture; (3), compression
+losses. The existence of the defect cannot be
+ascertained with any certainty without the use of an
+indicator or of some registering device which gives
+graphic records. Nevertheless, it is possible in some
+<!--144.png--><span class='pagenum'><a name="Page_144" id="Page_144">[144]</a></span>
+degree to detect retarded explosions, simply by observing
+whether there is a diminution in the power or
+an excessive consumption, despite the perfect operation
+and good condition of all the engine parts.</p>
+
+<p>In order to remedy the defect it should be ascertained
+if the compression is good, if the supply of gas
+is normal, and if the conditions under which the mixture
+of air and gas is produced have not been changed.
+Lastly, the ignition apparatus is gradually adjusted to
+accelerate its operation until a point is reached when,
+after explosion, shocks are produced which indicate an
+excessive advance. The ignition apparatus is then adjusted
+to a point slightly ahead of the corresponding
+position. Recalling the descriptions already given of
+the various systems of ignition, the manner of regulating
+the moment of ignition in each case may be summarized
+as follows:</p>
+
+<p>1. For the valveless incandescent tube, provided
+with a burner the position of which can be varied,
+ignition can be accelerated by bringing the burner
+nearer to the base. Retardation is effected by moving
+the burner away from the base.</p>
+
+<p>2. In the case of the incandescent tube of the fixed
+burner type, the moment of ignition will depend upon
+the length of the tube. The retardation will be greater
+as the tube is shorter, and <i>vice versa</i>.</p>
+
+<p>3. If the tube be provided with an ignition-valve,
+the time of ignition having been regulated by the
+maker, regulation need not be undertaken except if the
+valve-stem be worn or the controlling-cam be distorted.
+<!--145.png--><span class='pagenum'><a name="Page_145" id="Page_145">[145]</a></span>
+If these defects should be noted, the imperfect parts
+should be repaired or renewed.</p>
+
+<p>4. In electric igniters the controlling apparatus
+is generally provided with a regulating device which
+may be manipulated during the operation of the motor.
+If the manual adjustment of the regulating apparatus
+be unproductive of satisfactory results, it is advisable
+to ascertain whether the spark is being produced normally.
+Before the engine has come to a stop, one of
+the valve-casings is raised, and through the opening
+thus produced it is easily seen whether the spark is of
+sufficient strength, the engine in the meanwhile being
+turned by hand. Care should always be taken to purge
+the cylinder of the gas that it may contain, in order to
+prevent dangerous explosions. If the spark should
+prove to be too feeble, or if there be no spark at all, despite
+the fact that every part of the mechanism is properly
+adjusted, it may be inferred that the fault lies with
+the current and is caused by</p>
+
+<p>1. Imperfect contact with the binding-posts, with
+the conducting wire, or with the contact-breaking
+members;</p>
+
+<p>2. A short circuit in one of the dismembered pieces;</p>
+
+<p>3. The presence of a layer of oil or of caked grease
+forming an insulator, injurious to induction, between
+the armature and the magnets;</p>
+
+<p>4. A deposit of oil or moisture on the contact-breaking
+parts;</p>
+
+<p>5. The exhaustion of the magnets, which, however,
+occurs only after several years of use, except when the
+<!--146.png--><span class='pagenum'><a name="Page_146" id="Page_146">[146]</a></span>
+magneto has been subjected for a long time to a high
+temperature.</p>
+
+<p>The mere discovery of any of these defects sufficiently
+indicates the means to be adopted in remedying
+them.</p>
+
+<p><b>Lost Motion in Moving Parts.&mdash;</b>Lost motion of
+the moving parts is due to structural errors. Its cause
+is to be found in the insufficient size of the frictional
+bearing surfaces, and improper proportioning of shafts,
+pins, and the like. The result is a premature wear
+which cannot be remedied. Imperfect adjustment,
+lack of care, and bad lubrication, may also hasten the
+wear of certain parts. This wear is manifested in
+shocks, occurring during the operation of the engine,&mdash;shocks
+which are particularly noticeable at the moment
+of explosion.</p>
+
+<p>Besides the inconveniences mentioned, wearing of the
+gears and of the moving parts leads to derangement of
+the power-transmitting members.</p>
+
+<p>So far as the admission and exhaust valves are concerned,
+the wearing of the cams, rollers, and lever-pivots
+is evidenced by a retardation in the opening of
+these valves and an acceleration in their closing.</p>
+
+<p>The ignition, whatever may be the system employed,
+is affected by lost motion and is retarded. The engine
+appreciably loses in power, and its consumption becomes excessive.</p>
+
+<p><b>Overheated Bearings.&mdash;</b>Apart from the imperfect
+adjustment of a member, it may happen that the bushings
+of the main bearings of the ends of the connecting-rod,
+<!--147.png--><span class='pagenum'><a name="Page_147" id="Page_147">[147]</a></span>
+and of the piston-pivot, may become heated because
+of excessive play, or of too much tightening, or of
+a lack of oil, or of the employment of oil of bad quality.
+The overheating may lead to the binding of frictional
+surfaces and even to the fusion of bushings if they be
+lined with anti-friction metal. In order to avoid the
+overheating of parts, it is advisable, while the engine
+is running, to touch them from time to time with the
+back of the hand. As soon as the slightest overheating
+is felt, the temperature may be lowered often by liberal
+oiling. If this be inadequate and if for special reasons
+it is impossible to stop the engine, the overheated part
+may be cooled by spraying it with soapy water.</p>
+
+<p>If the overheating has not been detected or reduced
+in time, a characteristic odor of burnt oil will be perceived,
+accompanied by smoke. The part overheated
+will then have attained a temperature so high that it
+cannot be touched with the hand. Should this occur,
+it is inadvisable to employ oil, because it would immediately
+burn up and would only aggravate the conditions.
+Cotton waste should be carefully applied to
+the overheated member, and gradual spraying with
+soapy water begun.</p>
+
+<p>In special cases where the lubricating openings or
+channels are not likely to be obstructed, a little flowers
+of sulphur may be added to the oil, if this be very fluid.
+Castor oil may also be successfully employed.</p>
+
+<p>If the binding of the rubbing surfaces should prevent
+the reduction of the overheated member's temperature,
+the engine must necessarily be stopped, and the
+<!--148.png--><span class='pagenum'><a name="Page_148" id="Page_148">[148]</a></span>
+parts affected detached. All causes of binding are removed
+by means of a steel scraper. The surfaces of the
+bushings and of the shaft which they receive are
+smoothed with a soft file and then polished with fine
+emery paper. Before the parts are replaced, the precaution
+of ascertaining whether they touch at all points
+should be taken. Careful inspection and copious lubrication
+should, of course, be undertaken when the engine
+is again started.</p>
+
+<p><b>Overheating of the Cylinder.&mdash;</b>The overheating of
+the cylinder may be due to a complete lack of water
+in the jacket or to an accidental diminution in the quantity
+of water supplied. If this discovery is made too
+late, and if the cylinder has reached a very high temperature,
+the circulation of the water should not be
+suddenly re-established, because of the liability of
+breaking the casting. It is best to stop the engine and
+to restore the parts to their normal condition.</p>
+
+<p>It is well to recall at this point that if the calcareous
+incrustation of the water-jacket or the branch pipes
+should hinder the free circulation of water, cleaning is,
+of course, necessary. The jacket may be washed several
+times with a twenty per cent. solution of hydrochloric
+acid. After this treatment the jacket should, of
+course, be rinsed with fresh water before the piping of
+the water-circulating apparatus is again connected.</p>
+
+<p><b>Overheating of the Piston.&mdash;</b>If the overheating of
+the piston is not due to faulty adjustment, it may be
+caused by lack of oil or to the employment of a lubricant
+not suitable for the purpose. In a previous chapter
+<!--149.png--><span class='pagenum'><a name="Page_149" id="Page_149">[149]</a></span>
+the importance of using a special oil for cylinder
+lubrication has been insisted upon. The overheating
+of the piston can also result from that of the piston-pin.
+Should this be the case it is advisable to stop the engine,
+to ascertain the condition and the degree of lubrication
+of this member and its bearing. Overheating of
+the piston is manifested by an increase of the temperature
+of the cylinder at the forward end. If this overheating
+be not checked, binding of the piston in the
+cylinder is likely to result.</p>
+
+<p><b>Smoke Arising from the Cylinder.&mdash;</b>This is generally
+a sign either of overheating, which causes the
+oil to evaporate, or of an abnormal passage of gas,
+caused by the explosion. Abnormal passage of gas
+may result from wear or from distortion of the cylinder,
+or from wear or breakage of the piston-rings. The
+result is always the overheating of the cylinder and a
+reduction in compression and power.</p>
+
+<p>If the engine is well kept and shows no sign of wear,
+leakage may be caused simply by the fouling of the
+piston-rings, which then adhere in their grooves and
+have but insufficient play. This defect is obviated by
+cleaning the rings in the manner explained in Chapter
+VII.</p>
+
+<p>Lubrication is faulty when the quantity of lubricant
+supplied is either insufficient or too abundant, or when
+the oils employed are of bad quality. It has already
+been shown that insufficient lubrication and the utilization
+of bad oils leads to the overheating of the moving
+parts.
+<!--150.png--><span class='pagenum'><a name="Page_150" id="Page_150">[150]</a></span></p>
+
+<p>Insufficient lubrication may be caused by imperfect
+operation of the lubricators, or, particularly during
+cold weather, by too great a viscosity or congelation of
+the oil. If a lubricator be imperfect in its operation,
+the condition of its regulating mechanism should be ascertained,
+if it has any, and an examination made to discover
+any obstruction in the oil-ducts. Such obstructions
+are very likely to occur in new devices which have
+been packed in cotton waste or excelsior, with the result
+that the particles of the packing material often find
+their way into openings.</p>
+
+<p>An oil may be bad in quality because of its very
+nature, or because of the presence of foreign bodies.
+In either case an oil of better quality should be substituted.</p>
+
+<p>The freezing of oil by intense cold may be retarded
+by the addition of ordinary petroleum to the amount of
+10 to 20 per cent.</p>
+
+<p>An excess of oil in the bearings results simply in
+an unnecessary waste of lubricant, and the splashing
+of oil on the engine and about the room. If too much
+oil be used in the cylinder, grave consequences may be
+the result; for a certain quantity of the oil is likely to
+accumulate within the cylinder, where it burns and
+forms a caky mass that may be heated to incandescence
+and prematurely ignite the explosive mixture. Especially
+in producer-gas engines is an excess of cylinder-lubricant
+likely to cause such accidents. Indeed,
+the temperature of explosion not being as high as in
+street-gas engines, the excess oil cannot be so readily
+<!--151.png--><span class='pagenum'><a name="Page_151" id="Page_151">[151]</a></span>
+removed with certainty by evaporation or combustion.
+On the other hand, the compression of the mixture
+being generally higher, premature ignition is very
+likely to occur.</p>
+
+<p><b>Back Pressure to the Exhaust.&mdash;</b>How the pipes and
+chests for the exhaust should be arranged in order not
+to exert a harmful influence on the motor has already
+been explained. Even if the directions given have been
+followed, however, the exhaust may not operate properly
+from accidental causes. Among these causes may
+be mentioned obstructions in the form of foreign bodies,
+such as particles of rust, which drop from the interior
+of the pipes after the engine has been running
+for some time and which, accumulating at any place in
+the pipe, are likely to clog the passage. Furthermore,
+the products of combustion may contain atomized cylinder
+oil which finds its way into the exhaust-pipe.
+This oil condenses on the walls of the elbows and bends
+of the pipe in a deposit which, as it carbonizes, is converted
+into a hard cake and which reduces the cross-section
+of the passage, thereby constituting a true obstacle
+to the free exhaust of the gases.</p>
+
+<p>These various defects are manifested in a loss in
+engine power as well as in an abnormal elevation of
+the temperature of the parts surrounding the exhaust
+opening.</p>
+
+<p><b>Sudden Stops.&mdash;</b>Sudden stops are occasioned by
+faulty operation of the engine, and by imperfect fuel
+supply. Among the first class the chief causes to be
+mentioned are the following:
+<!--152.png--><span class='pagenum'><a name="Page_152" id="Page_152">[152]</a></span></p>
+
+<p>1. Overheating, which has already been discussed
+and which may block a moving part.</p>
+
+<p>2. Defective ignition.</p>
+
+<p>3. Binding of the admission-valve or of the exhaust-valve,
+preventing respectively suction or compression.</p>
+
+<p>4. The breaking or derangement of a member of the
+distributing mechanism.</p>
+
+<p>5. A weakening of the exhaust-valve spring, so that
+the valve is opened by the suction of fresh quantities of
+mixture.</p>
+
+<p>These faults are due to carelessness and improper inspection
+of the engine.</p>
+
+<p>So far as the fuel supply of the engine is concerned,
+the causes of stoppage will vary if street-gas or producer-gas
+be employed. In the former case the difficulty
+may be occasioned by the improper operation of
+the meter, by the formation of a water-pocket in the
+piping, by the binding of an anti-pulsator valve, by the
+derangement of a pressure-regulator, or by a sudden
+change in the gas pressure when no pressure-regulator
+is employed. If producer-gas be used, stoppages may
+be occasioned by a sudden change in the quality, quantity,
+or temperature of the gas. These defects will be
+examined in detail in the chapter on Gas-Producers.</p>
+
+<hr class="ChapterTopRule" />
+<!--153.png--><p><span class='pagenum'><a name="Page_153" id="Page_153">[153]</a></span></p>
+<h2><a name="CHAPTER_X" id="CHAPTER_X"></a>CHAPTER X</h2>
+
+<div class="c3">PRODUCER-GAS ENGINES</div>
+
+<p>Thus far only street-gas or illuminating-gas engines
+have been discussed. If the engine employed be small&mdash;10
+to 15 horse-power, for instance&mdash;street-gas is a
+fuel, the richness, purity and facility of employment
+of which offsets its comparatively high cost. But
+the constantly increasing necessity of generating
+power cheaply has led to the employment of special
+gases which are easily and cheaply generated. Such
+are the following:</p>
+
+<ul><li>Blast-furnace gases,</li>
+<li>Coke-oven gases,</li>
+<li>Fuel-gas proper,</li>
+<li>Mond gas,</li>
+<li>Mixed gas,</li>
+<li>Water-gas,</li>
+<li>Wood-gas.</li></ul>
+
+<p>The practical advantages resulting from the utilization
+of these gases in generating power were hardly
+known until within the last few years. The many uses
+to which these gases have been applied in Europe since
+1900 have definitely proved the industrial value of producer-gas
+engines in general.</p>
+
+<p>The steps which have led to this gradually increasing
+use of producer-gas have been learnedly discussed and
+commented upon in the instructive works and publications
+<!--154.png--><span class='pagenum'><a name="Page_154" id="Page_154">[154]</a></span>
+of Aim&eacute; Witz, Professor in the Faculty of
+Sciences of Lille, in those of Dugald Clerk, of London,
+F. Grover, of Leeds, and Otto G&uuml;ldner, of Munich,
+and in those of the American authors, Goldingham,
+Hiscox, Hutton, Parsell and Weed, etc. The
+new tendencies in the construction of large engines may
+be regarded as an interesting verification of the forecasts
+of these men&mdash;forecasts which coincide with the
+opinion long held by the author. Aim&eacute; Witz has
+always been an advocate of high pressures and of increased
+piston speed. English builders who made experiments
+in this direction conceded the beneficial results
+obtained; but while they increased the original
+pressure of 28 to 43 pounds per square inch employed
+five or six years ago to the pressure of 85 to 100 pounds
+per square inch nowadays advocated, the Germans, for
+the most part, have adopted, at least in producer-gas
+engines, pressures of 114 to 170 pounds per square
+inch and more.</p>
+
+<p><b>High Compression.&mdash;</b>In actual practice, the problem
+of high pressures is apparently very difficult of solution,
+and many of the best firms still seem to cling to
+old ideas. The reason for their course is, perhaps, to
+be found in the fact that certain experiments which they
+made in raising the pressures resulted in discouraging
+accidents. The explosion-chambers became overheated;
+valves were distorted; and premature ignition
+occurred. Because the principle underlying high pressures
+was improperly applied, the results obtained were
+poor.
+<!--155.png--><span class='pagenum'><a name="Page_155" id="Page_155">[155]</a></span></p>
+
+<p>High pressures cannot be used with impunity in cylinders
+not especially designed for their employment,
+and this is the case with most engines of the older type,
+among which may be included most engines of English,
+French, and particularly of American construction.
+In American engines notably, the explosion-chamber,
+the cylinder and its jacket, are generally cast in one
+piece, so that it is very difficult to allow for the free expansion
+of certain members with the high and unequal
+temperatures to which they are subjected (Fig. 22).</p>
+
+<p>Some builders have attempted to use high pressures
+without concerning themselves in the least with a modification
+of the explosive mixture. The result has been
+that, owing to the richness of the mixture, the explosive
+pressure was increased to a point far beyond that for
+which the parts were designed. Sudden starts and stops
+in operation, overheating of the parts, and even breaking
+of crank-shafts, were the results. The engines had
+gained somewhat in power, but no progress had been
+made in economy of consumption, although this was
+the very purpose of increasing the compression.</p>
+
+<p>High pressures render it possible to employ poor
+mixtures and still insure ignition. A quality of street-gas,
+for example, which yields one horse-power per
+hour with 17.5 cubic feet and a mixture of 1 part gas
+and 8 of air compressed to 78 pounds per square inch,
+will give the same power as 14 cubic feet of the same
+gas mixed with 12 parts of air and compressed to 171
+pounds per square inch.</p>
+
+<p>"Scavenging" of the cylinder, a practice which engineers
+<!--156.png--><span class='pagenum'><a name="Page_156" id="Page_156">[156]</a></span>
+of modern ideas seem to consider of much importance,
+is better effected with high pressures, for the
+simple reason that the explosion-chamber, at the end
+of the return stroke, contains considerably less burnt
+gases when its volume is smaller in proportion to that
+of the cylinder.</p>
+
+<p>In impoverishing the mixture to meet the needs of
+high pressures, the explosive power is not increased and
+in practice hardly exceeds 365 to 427 pounds per square
+inch. With the higher pressures thus obtained there
+is consequently no reason for subjecting the moving
+parts to greater forces.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_076.jpg" width="600" height="483" alt="Fig. 76." title="" />
+<span class="caption"><span class='smcap'>Fig. 76.</span>&mdash;Method of cooling the cylinder-head.</span>
+</div>
+
+<p><b>Cooling.&mdash;</b>The increase in temperature of the cylinder-head
+and of the valves, due wholly to high compression,
+is perfectly counteracted by an arrangement
+which most designers seem to prefer, and which, as
+shown in the accompanying diagram (Fig. 76), consists
+in placing the mixture and exhaust-valves in a
+passage forming a kind of antechamber completely
+<!--157.png--><span class='pagenum'><a name="Page_157" id="Page_157">[157]</a></span>
+surrounded by water. The immediate vicinity of this
+water assures the perfect and equal cooling of the valve-seats.
+This arrangement, while it renders it possible to
+reduce the size of the explosion-chamber to a minimum,
+has the additional mechanical advantage of enabling
+the builder to bore the seats and valve-guides
+with the same tool, since they are all mounted on the
+same line. From the standpoint of efficiency, the design
+has the advantage of permitting the introduction
+of the explosive mixture without overheating it as it
+passes through the admission-valve, which obtains all
+the benefit of the cooling of the cylinder-head, literally
+surrounded as it is by water.</p>
+
+<p>In large engines the cooling effect is even heightened
+by separately supplying the jackets of the cylinder-head
+and of the cylinder. In engines of less power the
+top of the cylinder-head jacket is placed in communication
+with that of the cylinder, so that the coldest water
+enters at the base of the head and, after having there
+been heated, passes around the cylinder in order finally
+to emerge at the top toward the center. The water having
+been thus methodically circulated, the useful effect
+and regularity of the cooling process is increased.</p>
+
+<p>Notwithstanding the care which is devoted to water
+circulation, it is advisable to run the producer-gas engine
+"colder" than the older street-gas types, in which
+the more economic speed is that at which the water
+emerges from the jacket at about a temperature of 104
+degrees F. It would seem advisable to meet the requirements
+of piston lubrication by reducing to a minimum
+<!--158.png--><span class='pagenum'><a name="Page_158" id="Page_158">[158]</a></span>
+the quantity of heat withdrawn by the circulating
+water. Indeed, the personal experiments of the author
+bear out this principle.</p>
+
+<p>For street-gas engines, however, the cylinders should
+be worked at the highest possible temperature consistent
+with the requirements of lubrication. It should not be
+forgotten that, in large engines fed with producer-gas,
+economy of consumption is a secondary consideration,
+because of the low quantity of fuel required. The cost,
+moreover, may well be sacrificed to that steadiness of
+operation which is of such great importance in large engines
+furnishing the power of factories; for in such
+engines sudden stops seriously affect the work to be
+performed. For this reason engine builders have been
+led to the construction of motors provided with very
+effective cooling apparatus. Since the circulation
+of the water around the explosion-chamber and the
+cylinder is not sufficient to counteract the rise of temperature,
+it has become the practice to cool separately
+each part likely to be subjected to heat. The seats of
+the exhaust-valves, the valves themselves, the piston,
+and sometimes the piston-rod, have been provided with
+water-jackets.</p>
+
+<p><b>Premature Ignition.&mdash;</b>Returning to the causes of the
+discouragements encountered by some designers who
+endeavored to use high pressures, it has already been
+mentioned that premature ignition of the explosive
+mixture in cylinders not suited for high pressures is one
+reason for the bad results obtained. An explanation of
+these results is to be found in the high theoretical temperature
+<!--159.png--><span class='pagenum'><a name="Page_159" id="Page_159">[159]</a></span>
+corresponding with great pressures and in the
+quantity of heat which must be absorbed by the walls
+of the explosion-chamber. These two circumstances
+are in themselves sufficient to produce spontaneous ignition
+of excessively rich mixtures, compressed in an overheated
+chamber unprovided with a sufficient circulation
+of water. A third cause of premature ignition may also
+be found in the old system of ignition which, in most
+English engines, consists of a metallic or porcelain tube,
+the interior of which communicates with the explosion-chamber,
+an exterior flame being employed to heat the
+tube to incandescence. In tubes of this type which are
+not provided with a special ignition-valve, the time of
+ignition is dependent only on the moment when the explosive
+mixture, driven into the tube, comes into contact,
+at the end of the compression stroke, with the incandescent
+zone, thereby causing the ignition. This
+very empirical method leads either to an acceleration
+or retardation of the ignition, depending upon the
+temperature of the tube, the position of the red-hot zone,
+its dimensions, and the temperature of the mixture,
+which is determined by the load of the engine. Although
+this system, the only merit of which is its simplicity,
+may meet the requirements of small engines,
+there is not the slightest doubt that it is quite inapplicable
+to those of more than 20 to 25 horse-power, for
+in such engines greater certainty in operation is demanded.
+Even if only the more improved of the two
+types of hot-tube ignition be considered, with or without
+valves, it must still be held that they are inapplicable
+<!--160.png--><span class='pagenum'><a name="Page_160" id="Page_160">[160]</a></span>
+to high compression engines. The ignition-valve
+is the part which suffers most from the high temperature
+to which it is subjected. Its immediate
+proximity to the incandescent tube, and its contact
+with the burning gas when it flares up, render
+it almost impossible to employ any cooling arrangement.
+Although with the exercise of great care it may
+work satisfactorily in engines of normal pressure, it is
+evident that it cannot meet the requirements of high pressure
+engines, because the temperature of the compressed
+mixture is such that the charge is certain to
+catch fire by mere contact with the overheated valve.
+In industrial engines of small size, premature ignition
+has little, if any, effect except upon silent operation and
+economic consumption. This does not hold true, however,
+of large engines. Besides the inconveniences mentioned,
+there is also the danger of breaking the cranks
+or other moving parts. The inertia of these members is
+a matter of some concern, because of their weight and
+of the linear speed which they attain in large engines.
+Some idea of this may be obtained when it is considered
+that in a producer-gas or blast-furnace-gas engine having
+a piston diameter of 24 inches and an explosive
+pressure of 299 pounds per square inch, the force exerted
+at the moment of explosion is about 132,000
+pounds. Naturally, engine builders have adopted the
+most certain means of avoiding premature ignition and
+its grave consequences.</p>
+
+<p>The method of ignition which at present seems to be
+preferred to any other for producer-gas is that employing
+<!--161.png--><span class='pagenum'><a name="Page_161" id="Page_161">[161]</a></span>
+a break-spark obtained with the magneto apparatus
+previously described. Some builders of large engines,
+particularly desirous of assuring steadiness of running,
+have provided the explosion-chamber with two independent
+igniters. It may be that they have adopted
+this arrangement largely for the purpose of avoiding
+the inconveniences resulting from a failure of one of the
+igniters, rather than for the purpose of igniting the
+mixture in several places so as to obtain a more uniform
+ignition and one better suited for the propagation of
+the flame.</p>
+
+<p><b>The Governing of Engines.&mdash;</b>Various methods have
+been adopted for the purpose of varying the motive
+power of an engine between no load and full load,
+still preserving, however, a constant speed of rotation.
+These methods consist in changing either the quantity
+or the quality of the mixture admitted into the cylinder.
+Thus it may happen that an engine may be supplied:</p>
+
+<p>1. With a mixture constant in quality and in quantity;</p>
+
+<p>2. With a mixture variable in quality and constant
+in quantity;</p>
+
+<p>3. With a mixture constant in quality and variable
+in quantity.</p>
+
+<p>1. <i>Mixture Constant in Quality and Quantity.&mdash;</i>This
+method implies the use of the hit-and-miss system of
+admission, in which the number of admissions and explosions
+varies, while the value or the composition of
+each admitted charge remains as constant as the compression
+itself (Fig. 34). This system has already been
+<!--162.png--><span class='pagenum'>162</span>
+referred to and its simplicity fully set forth. By its
+use a comparatively low consumption is obtained, even
+when the engine is not running at full load. On the
+other hand, it has the disadvantage of necessitating the
+employment of heavy fly-wheel to preserve cyclic regularity.</p>
+
+<p>2. <i>Mixture Variable in Quality and Constant in
+Quantity.&mdash;</i>The governing system most commonly employed
+to obtain a mixture variable in quality and constant
+quantity is based upon the control of the gas-admission
+valve by means of a cam having a conical
+longitudinal section, as shown in Fig. 35. This cam,
+commonly called a "conical cam," is connected with a
+lever actuated from the governor. As the lever swings
+under the action of the governor, the cam is shifted
+along the half-speed shaft of the engine. The result is
+that the gas-admission valve is opened for a longer or
+shorter period.</p>
+
+<p>In another system a cylindrical valve is mounted
+between the chamber in which the mixture is formed
+and the gas-supply pipe, the valve being carried on the
+same stem as the mixture-valve itself. The cylindrical
+valve is displaced by the governor so as to vary the
+quantity of gas drawn in with relation to the quantity
+of air.</p>
+
+<p>When the engines are fed with producer-gas the
+parts which have just been described should be frequently
+inspected and cleaned; for they are only too
+easily fouled.</p>
+
+<p>Engines thus governed should be run at high pressure
+<!--163.png--><span class='pagenum'>163</span>
+so as to insure the ignition of the producer-gas
+mixtures formed when the position of the cam corresponds
+with the minimum opening of the gas-valve.
+Powerful governors should be employed, capable of
+overcoming the resistance offered by the cylindrical
+valve or the cam.</p>
+
+<p>It may often happen that variations in the load of the
+engine render it necessary to actuate the air valve, so
+as to obtain a mixture which will be ignited and exploded
+under the best possible conditions.</p>
+
+<p>3. <i>Mixture Constant in Quality and Variable in
+Quantity.</i>&mdash;In supplying an engine with a mixture constant
+in quality and variable in quantity, the compression
+does not remain constant. The quantity of mixture
+drawn in by the cylinder may even be so far reduced
+that the pressure drops below the point at which ignition
+takes place. For that reason engines of this type
+should be run at high pressures.</p>
+
+<p>The variation of the quantity of mixture may be
+effected in various ways. The simplest arrangement
+consists in mounting a butterfly-valve in the mixture
+pipe, which valve is controlled by the governor and
+throttles the passage to a greater or lesser degree.
+A very striking solution of the problem consists in varying
+the opening of the mixture-valve itself. To attain
+this end the valve is moved by levers. The point of
+application of one of these levers is displaced under
+the action of the governor so as to vary the travel of
+the valve within predetermined limits. Under these
+conditions a mixture of constant homogeneity is introduced
+<!--164.png--><span class='pagenum'>164</span>
+into the cylinder, so proportioned as to insure
+ignition even at low pressures.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_076a.jpg" width="600" height="323" alt="Fig. 76a." title="" />
+<span class="caption"><span class='smcap'>Fig. 76</span><i>a</i>.&mdash;Governing system for
+producer-gas engines.</span>
+</div>
+
+<p>In recent experiments conducted by the author it was
+proved that with this governing system ignition still
+takes place even though the pressure has dropped to
+43 pounds per square inch. This system has the merit
+of rendering it possible to employ ordinary governors
+of moderate size, since the resistance to be overcome
+at the point of application of the lever is comparatively
+small. In the accompanying illustration the Otto
+Deutz system is illustrated.</p>
+
+<hr class="ChapterTopRule" />
+<!--165.png--><p><span class='pagenum'><a name="Page_165" id="Page_165">[165]</a></span></p>
+<h2><a name="CHAPTER_XI" id="CHAPTER_XI"></a>CHAPTER XI</h2>
+
+<div class="c3">PRODUCER-GAS</div>
+
+<p>It may here be not amiss to point out the differences
+between illuminating gas and those gases which are
+called in English "producer" gases, and in French
+"poor" gases, because of their low calorific value.</p>
+
+<p><b>Street-Gas.&mdash;</b>This gas, the composition of which
+varies with different localities, has a calorific value,
+which is a function of its composition, and which varies
+from 5,000 to 5,600 calories per cubic meter (19,841 to
+24,896 B.T.U. per 35.31 cubic feet) measured at constant
+pressure and corrected to 0 degrees C. (32 degrees
+F.) at a pressure of 760 millimeters (29.9 inches of
+mercury, or atmospheric pressure), not including the
+latent heat of the water of condensation. The following
+table gives the average volumetric composition of
+illuminating gas in various cities:</p>
+
+<div class='center'>
+<table border="1" cellpadding="4" cellspacing="0" summary="City gas composition in various places.">
+<tr><td></td><td colspan='5'>Cities.</td></tr>
+<tr><td></td>
+<td>London.</td><td>Manchester.</td>
+<td>New York.</td><td>Paris.</td>
+<td>Berlin.</td></tr>
+<tr><td>Hydrogen</td><td>48</td>
+<td>46</td><td>40</td><td>52</td>
+<td>50</td></tr>
+<tr><td>Carbon monoxide</td><td>4</td>
+<td>7</td><td>4</td><td>6</td>
+<td>9</td></tr>
+<tr><td>Methane</td><td>38</td><td>35</td>
+<td>37</td><td>32</td><td>33</td></tr>
+<tr><td>Various hydrocarbons</td><td>4</td>
+<td>6</td><td>7</td><td>6</td>
+<td>5</td></tr>
+<tr><td>Carbon dioxide</td><td>...</td><td>4</td>
+<td>3</td><td>...</td><td>2</td></tr>
+<tr><td>Nitrogen</td><td>5</td><td>2</td>
+<td>8</td><td>4</td><td>1</td></tr>
+<tr><td>Oxygen</td><td>1</td><td>...</td>
+<td>1</td><td>...</td><td>...</td></tr>
+<tr><td>&nbsp;</td>
+<td>100</td><td>100</td>
+<td>100</td><td>100</td><td>100</td></tr>
+</table></div>
+<!--166.png--><p><span class='pagenum'><a name="Page_166" id="Page_166">[166]</a></span></p>
+
+<p>Furthermore, these constituents vary within certain
+limits. This is also true of the calorific value. Experiments
+made by the author have demonstrated that in
+the same place at an interval of a few hours, variations
+of approximately ten per cent. occur.</p>
+
+<p><b>Composition of Producer-Gases.&mdash;</b>The average
+chemical composition of producer-gases varies with the
+conditions under which they are generated and the nature
+of the fuel. The following are the proportions of
+its constituents expressed volumetrically:</p>
+
+<div class='center'>
+<table border="1" cellpadding="4" cellspacing="0" summary="Producergas composition.">
+<tr><td></td><td colspan='6'>Gas.</td></tr>
+<tr><td></td><td>Blast Furnace.</td><td>Producer.</td>
+<td>Mond.</td><td>Mixed (Fichet).</td>
+<td>Water (Stache).</td>
+<td>Wood (Rich&eacute;).</td></tr>
+<tr><td>Nitrogen and oxygen</td><td>60</td>
+<td>59</td><td>42</td><td>50</td>
+<td>5</td><td>1</td></tr>
+<tr><td>Carbon monoxide</td><td>24</td>
+<td>25</td><td>11</td><td>20</td>
+<td>40</td><td>29</td></tr>
+<tr><td>Carbon dioxide</td><td>12</td>
+<td>5</td><td>16</td><td>7</td>
+<td>4</td><td>11</td></tr>
+<tr><td>Hydrocarbons</td><td>2</td>
+<td>2</td><td>2</td><td>3</td>
+<td>1</td><td>15</td></tr>
+<tr><td>Hydrogen</td><td>2</td>
+<td>9</td><td>29</td><td>20</td>
+<td>50</td><td>44</td></tr>
+
+<tr><td>&nbsp;</td><td>100</td><td>100</td>
+<td>100</td><td>100</td><td>100</td>
+<td>100</td></tr>
+<tr><td>Calorific value in calories.</td><td>950</td>
+<td>1,100</td><td>1,400</td>
+<td>1,300</td><td>2,400</td><td>2,960</td></tr>
+<tr><td>Average weight of a cubic <br />meter in kilos</td>
+<td>1.30</td><td>1.1</td><td>1.02</td>
+<td>1.05</td><td>0.680</td><td>0.824</td></tr>
+<tr><td>Or of a cubic foot in<br />pounds</td>
+<td>0.008</td><td>0.007</td><td>0.006</td>
+<td>0.0068</td><td>0.0042</td><td>0.0051</td></tr>
+</table></div>
+
+<p>Blast-furnace gas has been used for generating power
+by means of gas-engines for about ten years. At the
+present time it is used in engines of very high power,
+a discussion of which engines more properly belongs
+to a work on metallurgy, and has no place, therefore,
+in a manual such as this.</p>
+
+<p>Producer-gas, in the true sense of the term, is generated
+in special apparatus either under pressure or by
+<!--167.png--><span class='pagenum'><a name="Page_167" id="Page_167">[167]</a></span>
+suction in a manner to be described in the following
+chapters.</p>
+
+<p>Mond gas is produced in generators of the blowing
+or pressure type from bituminous coal, necessitating the
+employment of special purifiers and permitting the collection
+of the by-products of the fractional distillation
+of the coal. Mond gas plants are, therefore, rather
+complicated and can be advantageously utilized only
+for large engines. More exhaustive information can
+be obtained from the descriptions published by the
+builders of Mond gas generators.</p>
+
+<p>Mixed gas is generated in apparatus arranged so that
+the retort is kept at a high temperature, thereby producing
+a gas richer in hydrogen than that made by producers.
+It should be observed that in practice the generators
+at present used yield a producer-gas, the calorific
+value of which fluctuates between 1,000 and 1,400
+calories per cubic meter (3,968 to 5,158 B.T.U. per
+35.31 cubic feet); and the composition varies accordingly,
+in the manner that has already been indicated
+in the tables for producer-gas and mixed gas. There
+is no necessity, therefore, for drawing a distinction between
+these two qualities of gas.</p>
+
+<p>Water-gas should theoretically be composed of 50
+per cent. carbon monoxide and 50 per cent. hydrogen,
+resulting from the decomposition of steam by incandescent
+coal. In practice, however, it contains a
+little nitrogen and carbon dioxide. The gas is obtained
+from generators in which air is alternately blown in to
+fan the fire and then steam to produce gas. Water-gas
+<!--168.png--><span class='pagenum'><a name="Page_168" id="Page_168">[168]</a></span>
+is employed in soldering on account of its reducing
+properties and of the high temperature of its flame.
+The great quantity of carbon monoxide which it contains
+renders it very poisonous and exceedingly dangerous,
+because it is generated under pressure. From the
+economical standpoint, its generation is more expensive
+than that of producer-gas, for which reason its
+employment in gas-engines is hardly of much value.</p>
+
+<p>Wood-gas, the composition of which has already been
+given, is generated in apparatus of the Rich&eacute; type, the
+principle of which consists in heating a cast retort
+charged with any kind of fuel, namely wood, and vertically
+mounted on a masonry base.</p>
+
+<p>This apparatus should be of particular interest to
+the proprietors of sawmills, furniture factories, and the
+like, since it offers a means of using the waste products
+of their plants.</p>
+
+<p>The relatively high proportion of carbon monoxide
+in producer-gas is objectionable from a hygienic standpoint,
+so much so, indeed, that it has attracted the attention
+of manufacturers. Carbon monoxide, the specific
+gravity of which is 0.967, is a gas peculiarly poisonous
+and dangerous. It cannot be breathed without baneful
+effects, and is even more dangerous than carbonic-acid
+gas, which eventually causes asphyxiation by reducing
+the quantity of oxygen in the air. For this reason, it is
+necessary to take the utmost precaution in efficiently and
+continuously ventilating the rooms in which the gas-generators
+and their accessories are installed. This
+suggestion should be followed, above all, when the apparatus
+<!--169.png--><span class='pagenum'><a name="Page_169" id="Page_169">[169]</a></span>
+in question are installed in cellars and basements.
+As a further precaution, where the plant is
+rather large a workman should not be allowed to enter
+the generator room alone.</p>
+
+<p>Blowing-generators, or those in which the gas is produced
+under pressure, are more dangerous than suction-generators.
+In the former a leaky joint may cause
+the vitiation of the surrounding air as the producer-gas
+escapes; in the suction apparatus the same fault simply
+causes more air to be drawn in.</p>
+
+<p>Dr. Melotte recommends the following procedure
+in cases of carbon monoxide asphyxiation:</p>
+
+<div class="center"><span class="smcap">Carbon Monoxide Asphyxiation</span></div>
+
+<p>Cases of poisoning by carbon monoxide are both frequent
+and dangerous. The gas is extremely poisonous,
+and all the more dangerous because it is odorless, colorless
+and tasteless. When it comes into contact with the
+blood, it forms a combination so stable that it is reacted
+upon by the oxygen of the air only with difficulty. It
+follows, therefore, that with each respiration of air
+charged with carbon monoxide, a certain quantity of
+blood is poisoned. In consequence of this, there is a
+possibility of poisoning in open air.</p>
+
+<p><b>Symptoms.&mdash;</b>The symptoms observed will vary with
+the manner in which the blood has been poisoned.
+There are two ways in which this poisoning can occur.
+The one depends upon whether the atmosphere contains
+an excess of carbon monoxide; the other whether the
+air breathed contains only traces of the gas.
+<!--170.png--><span class='pagenum'><a name="Page_170" id="Page_170">[170]</a></span></p>
+
+<p><b>Gradual, Rapid Asphyxiation.&mdash;</b>At first a vague
+sickness is felt, rapidly followed by violent headaches,
+vertigo, anxiety, oppression, dimness of vision, beating
+of the pulse at the temples, hallucinations, and an irresistible
+desire to sleep. If at this stage the patient has a
+sufficient idea of danger to prompt him to open a
+window or door, he will escape death.</p>
+
+<p>In the second stage, the victim's legs are paralyzed,
+but he can still move his arms and his head. The mind
+still preserves its clearness, and in a measure assists the
+further process of asphyxiation because of its impotency.
+Then follow coma and death.</p>
+
+<p><b>Slow, Chronic Asphyxiation.&mdash;</b>Slow, chronic asphyxiation
+is not infrequent. Its symptoms are often
+difficult to detect. Poisoning is manifested by weakness,
+cephalalgia, vomiting, pallor, general anemia, lassitude,
+and local paralysis. If any of these symptoms
+appear in the men who work in the vicinity of the producers,
+immediate steps should be taken to prevent the
+possibility of carbon monoxide asphyxiation.</p>
+
+<div class="center"><span class="smcap">
+First Aid in Cases of Carbon Monoxide Poisoning</span></div>
+
+<p>It has already been stated that the oxygen of the air
+has no oxidizing effect upon blood contaminated by
+carbon monoxide. Only a liberal current of pure
+oxygen can oxidize the combination formed and render
+hematosis possible. This liberal current can be obtained
+from an oxygen tank of the portable variety, provided
+with a tube carrying at its free end a mask which
+<!--171.png--><span class='pagenum'><a name="Page_171" id="Page_171">[171]</a></span>
+is held over the mouth and the nostrils. The absorption
+of gas takes place by artificial respiration, which is
+effected in several ways. The most practical of these
+are the Sylvester and Pacini methods.</p>
+
+<p><b>Sylvester Method.&mdash;</b>The patient is laid on his back.
+His arms are raised over his head and then brought
+back on each side of the body. This operation is repeated
+fifteen times per minute approximately. The
+method is very frequently employed and is excellent in
+its results.</p>
+
+<p><b>The Pacini Method.&mdash;</b>Four fingers are placed in
+the pit of the arm, with the thumb on the shoulder.
+The shoulder is then alternately raised and lowered,
+producing a marked expansion of the chest. This
+method is the more effective of the two. The movements
+described are repeated fifteen to twenty times
+each minute very rhythmically.</p>
+
+<p>One or the other of these two methods of treatment
+should be immediately applied in serious cases. Certain
+preliminary precautions should be taken in all
+cases, however. The patient should be carried to a well-ventilated
+and moderately heated room, stripped of his
+clothes, and warmed by water-bottles and heated linen.
+Reflex action should be excited, the peripheral nervous
+system stimulated in order to contract the heart and the
+respiratory muscles, and the precordial region cauterized.
+In addition to this treatment, the region of the diaphragm
+should be rubbed and pinched, the skin rubbed,
+cold showers given, flagellations administered, urtications
+(whipping with nettles) undertaken, the skin and
+<!--172.png--><span class='pagenum'><a name="Page_172" id="Page_172">[172]</a></span>
+the mucous membranes excited, the mucous membrane
+of the nose and of the pharynx titillated with a feather
+dipped in ammonia, alcohol, vinegar, or lemon juice.
+Rhythmic traction of the tongue is effective when carried
+out as follows: The tongue is seized with a forceps
+and kept extended by means of a coarse thread. It is
+then pulled out from the mouth sharply and allowed to
+reenter after each traction. These movements should
+be rhythmic and should be repeated fifteen to twenty
+times a minute.</p>
+
+<p>All these efforts should be continued for several
+hours. When the patient has finally been revived, he
+should be placed in a warm bed. Stimulants such as
+wine, coffee, and the like should be administered. If
+the head should be congested, local blood-letting should
+be resorted to and four or six leeches applied behind
+the ears. It should be borne in mind that the various
+steps enumerated are to be taken pending the arrival
+of a physician.</p>
+
+<div class="center"><span class="smcap">Impurities of the Gases</span></div>
+
+<p>Most of the coal used in generating producer-gas
+contains sulphur. Sulphuretted hydrogen is thus produced,
+which mixes with the gas and imparts to it its
+characteristic odor. In some gas-generators, purifiers
+are employed in which sawdust mixed with iron salts
+is utilized, with the result that a combination is formed
+with the sulphuretted hydrogen, thereby removing it
+from the producer-gas. In other forms of generators
+<!--173.png--><span class='pagenum'><a name="Page_173" id="Page_173">[173]</a></span>
+a more summary method of purification is adopted, so
+that traces of sulphuretted hydrogen still remain.
+Since this gas attacks copper, the employment of this
+metal is not advisable for the following apparatus:
+Generator (openings, cock for testing the gas); piping
+(gas-pressure cocks, drain and pet cocks); engine (gas-admission
+cock, lubricating joint in the cylinder, valves
+and cocks of the compressed-air starting-pipe).</p>
+
+<p>The distillation of coal in generators results in the
+formation of ammonia gas. This also has a corrosive
+action on copper and its alloys; but owing to its great
+solubility, it is eliminated by the waters of the "scrubber"
+and does not reach the engine.</p>
+
+<div class="center"><span class="smcap">Production and Consumption</span></div>
+
+<p>The quantity of gas produced in most generators
+varies from 6.4 to 8.2 pounds per cubic foot of raw coal
+burnt in the generator. The engine consumes per
+horse-power per hour 70 to 115 cubic feet of gas, depending
+upon its richness.</p>
+
+<hr class="ChapterTopRule" />
+<!--174.png--><p><span class='pagenum'><a name="Page_174" id="Page_174">[174]</a></span></p>
+<h2><a name="CHAPTER_XII" id="CHAPTER_XII"></a>CHAPTER XII</h2>
+
+<div class="c3">PRESSURE GAS-PRODUCERS</div>
+
+<p>As we have already seen, producer-gas as a fuel for
+engines may be generated in two kinds of apparatus, the
+one operating under pressure, and the other by suction.</p>
+
+<p><b>Dowson Gas-Producers.&mdash;</b>The first pressure-generators
+were introduced by Dowson of London and
+necessitated installations of quite a complicated nature.
+Later improvements made by the designers contributed
+much to the general employment of their system.
+Many installations varying from 50 to 100 horsepower
+and more may be found in the United Kingdom,
+all of them made by Dowson. Indeed, for a long time
+the name of Dowson was coupled with producer-gas
+itself. The Dowson system necessitates the utilization
+of anthracite or of comparatively hard coal, such as
+that mined in Wales and Pennsylvania. Owing to the
+necessity of employing this special quality of coal the
+Dowson system and the systems that sprang from it
+were burdened with cooling, washing, and purifying
+apparatus, which complicated the installations to such
+an extent that they resembled gas works. The generator
+that took the place of the retort was fed with air
+and steam, blown in under pressure, necessitating the
+employment of a boiler. Furthermore, the production
+<!--175.png--><span class='pagenum'>175</span>
+of the gas under pressure necessitated the use of a gasometer
+for its collection before it was supplied to the
+engine-cylinder. Such Installations were evidently
+costly, and were, moreover, difficult to maintain in
+proper working order. Nevertheless, there are many
+cases in which they must be industrially employed.
+<!--176.png--><span class='pagenum'>176</span></p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_077.jpg" width="600" height="307" alt="Fig. 77." title="" />
+<span class="caption"><span class='smcap'>Fig. 77.</span>&mdash;A complete Dowson producer-gas plant.</span>
+</div>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_078.jpg" width="600" height="244" alt="Fig. 78." title="" />
+<span class="caption"><span class='smcap'>Fig. 78.</span>&mdash;A Simplex producer-gas plant.</span>
+</div>
+<!--177.png--><p><span class='pagenum'><a name="Page_177" id="Page_177">[177]</a></span></p>
+
+<p>Among these may be cited works in which producer-gas
+is employed as a furnace fuel or as a soldering or
+roasting medium. Still other cases are those in which
+the producer-gas must be piped to some distance from
+a central generating installation to various engines,
+in the manner rendered familiar in gas-lighting practice.</p>
+
+<p>Most pressure gas-generators have been copied from
+the original type invented by Dowson. These include
+a generator in which the gas is produced; an injector
+fed by a boiler; a fan or a compressor by means of
+which a mixture of steam and air is blown under the
+generator-furnace; washing apparatus termed "scrubbers";
+gas-purifying apparatus; and a gas-holder
+(Fig. 77).</p>
+
+<p><b>Generators.&mdash;</b>The generator consists of a retort made of refractory clay,
+vertically mounted, and cylindrical or conical in form. This retort is
+protected on its exterior by a metal jacket with an intermediate layer
+of sand which serves to reduce the heat lost by radiation. The fuel is
+charged through the top of the retort, which is provided with a double
+closure in order to prevent the entrance of air during the charging
+operation. The generator rests on a grid arranged at the base of the
+retort, upon which grid the ashes fall. The outlet of the injector-pipe
+opens into the ash-pit, and this injector constantly supplies a mixture
+of steam and air. The mixture is generally superheated by passing it
+through a coil arranged in the fire-box of the boiler, in the generator,
+or in the outlet for burnt gases. Sometimes the
+<!--178.png--><span class='pagenum'><a name="Page_178" id="Page_178">[178]</a></span> air is subjected to a
+preliminary heating by recuperating in some way the waste heat of the
+apparatus.</p>
+
+<p>The chief features in the arrangement of generators which have received
+the attention of manufacturers are the following: Good distribution of
+the fuel in charging; easy descent of the fuel; reduction of the
+destructive action of the clinkers on the walls; means for cleaning the
+grate without interfering with the generation of gas; prevention of
+leakage. Many devices have been employed to fulfil these requisites.</p>
+
+<p>A perfect distribution of the fuel during charging is attained chiefly
+by the form of the hopper, and of its gate, which is generally conical.
+In most apparatus the gate opens toward the interior of the generator,
+and the inclination of its walls causes a uniform scattering of the fuel
+in the retort. It is all the more necessary to disperse the fuel in this
+manner when the cross-section of the retort is small compared with its
+height.</p>
+
+<p><i>The facility of the fuel's</i> descent is dependent largely upon the
+nature and the size of the coal employed. Porous coal gives better
+results than dense and compact coal. It is therefore preferable to
+employ screened coal free from dust in pieces each the size of a
+hazel-nut. The various sections given to the interior, including as they
+do cylindrical forms, truncated at the summit or the base, partially
+truncated toward the base and the like, would lead to the conclusion
+that this question is not of the importance which some writers would
+have us believe. Still, it must be considered that if the fuel drops
+slowly, its prolonged detention within
+<!--179.png--><span class='pagenum'><a name="Page_179" id="Page_179">[179]</a></span> the walls of the hopper and its
+transformation into fusible slag may result in a disintegration of the
+refractory lining of the furnace.</p>
+
+<p>The quantity of steam injected, greater or less, according to the nature
+of the fuel, renders it possible to obtain friable slags and
+consequently to prevent grave injury to the retort. Red-ash coal is in
+general fusible, containing as it does some iron. Its temperature of
+fusion varies between 1,832 to 2,732 degrees F.</p>
+
+<p><i>Cleanliness</i> is most important so far as the operation of the generator
+is concerned. It should be possible to scrape the generator during
+operation without changing the composition of the gas, when the
+incandescent zone is chilled, or an excess of air is introduced, or the
+steam-injector be momentarily thrown out of operation. Mechanical
+cleaners with movable grates or revolving beds have the merit of causing
+the ashes to drop without interfering with the operation of the
+apparatus. The same meritorious feature is characteristic of ash-pits
+having water-sealed joints.</p>
+
+<p>Pressure gas-generators need not be as perfectly gas-tight as suction
+apparatus. Leakage of gas, which is usually manifested by a
+characteristic odor, results in a loss of consumption and renders the
+air unfit to breathe.</p>
+
+<p>A generator should be provided in its upper part with openings through
+which a poker can easily be introduced in order to shake up the fuel and
+to dislodge the clinkers which tend to form and which cause the
+principal defects in operation, particularly with fuels that tend to
+swell, cake, and adhere to the furnace walls
+<!--180.png--><span class='pagenum'><a name="Page_180" id="Page_180">[180]</a></span> when heated. Many
+apparatus, moreover, are provided with lateral openings having mica
+panes through which the progress of combustion can be observed (Fig.
+79).</p>
+
+<div class="figcenter" style="width: 319px;">
+<img src="images/fig_079.jpg" width="319" height="600" alt="Fig. 79." title="" />
+<span class="caption"><span class='smcap'>Fig. 79.</span>&mdash;Fichet-Heurtey producer with
+rotating bed-plate.</span>
+</div>
+
+<p><b>Air-Blast.&mdash;</b>The system by which air and steam are injected necessitates
+the employment of a steam-boiler of 75 pounds pressure. This method of
+blowing, which is rather complicated, has the disadvantage of varying
+<!--181.png--><span class='pagenum'><a name="Page_181" id="Page_181">[181]</a></span>
+in feed with the pressure of the steam in the boiler, which pressure is
+not easily maintained at a given number of pounds per square inch.
+Moreover, when more or less resistance is offered by the fuel in the
+generator the quantity of air which is injected is likely to be
+diminished in quantity while the quantity of steam remains the same. The
+result is a change in speed which follows from the modification of the
+proportions of the two elements. For these reasons some manufacturers
+have resorted of late years to the employment of fans and blowers.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_080.jpg" width="600" height="155" alt="Fig. 80." title="" />
+<span class="caption"><span class='smcap'>Fig. 80.</span>&mdash;Koerting blower.</span>
+</div>
+
+<p><b>Blowers.&mdash;</b> The fans or blowers employed vary considerably in
+arrangement. Most of them are based on the Koerting system (Fig. 80),
+and comprise essentially (1) a tube through which the steam is supplied
+under pressure, and (2) a cylindro-conical blast-pipe. The tube is
+placed in the axis of the blast-pipe at its outer opening. As it escapes
+under pressure the steam is caught in the blast-pipe and draws with it a
+certain quantity of air, which can be regulated. It is important that
+these injection blowers should operate in such a manner that the
+pressure and the feed of air and steam can be controlled.</p>
+
+<p><b>Fans.&mdash;</b>Mechanical blowers have the advantage of
+<!--182.png--><span class='pagenum'><a name="Page_182" id="Page_182">[182]</a></span> dispensing with the
+employment of steam under pressure and the consequent installation of a
+boiler (Fig. 78). Driven by the engine itself or from some separate
+source of power, these apparatus are easily placed in position, require
+no great amount of attention, and utilize but little energy. They are
+either of the centrifugal type or of the rotary type, exemplified in the
+Root blower (Fig. 81). The latter system has the advantage of high
+efficiency, and of enabling comparatively high pressures&mdash;19 to 27
+inches of water&mdash;to be attained, which, however, are used only for
+special fuels, such as lignite, peat, and the like. The air supplied by
+the blower, before reaching the fire-box, is superheated, either before
+or after it is charged with steam.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_081.jpg" width="600" height="525" alt="Fig. 81." title="" />
+<span class="caption"><span class='smcap'>Fig. 81.</span>&mdash;Root blower.</span>
+</div>
+
+<p><b>Compressors.&mdash;</b>In some installations air is supplied by compressor under
+the high pressure of 70 to 90 pounds per square inch, and seem well
+adapted to the production of a gas of good quality. Moreover, neither
+<!--183.png--><span class='pagenum'><a name="Page_183" id="Page_183">[183]</a></span>
+tar nor ammoniacal waters are produced. The Gardie producer may be
+considered typical of this class of apparatus (Fig. 82). The chief
+feature of this producer is to be found in simple washing and purifying
+apparatus. It may be well to state here that the compression of air at
+high pressure occasions some complications, and a considerable
+expenditure of power.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_082.jpg" width="600" height="398" alt="Fig. 82." title="" />
+<span class="caption"><span class='smcap'>Fig. 82.</span>&mdash;Gardie producer.</span>
+</div>
+
+<p><b>Exhausters.&mdash;</b>Some designers have invented devices which draw gas into
+the generator whence it is supplied to the engines, these suction
+apparatus being connected with the blowers or used separately. But with
+the exception of a few special instances, such arrangements are not
+widely used&mdash;at least not for the production of motive power alone.</p>
+
+<p>Whatever may be the arrangement employed for the
+<!--184.png--><span class='pagenum'><a name="Page_184" id="Page_184">[184]</a></span> introduction of a
+mixture of air and steam under the grate of the generator, the
+blast-pipe as a general rule discharges toward the center of the
+apparatus. Still, in large producers it becomes desirable to provide a
+means for varying the quantity of air and steam within wide limits so as
+to regulate the heat of the fire. For that reason several outlets are
+symmetrically arranged below the fuel.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_083.jpg" width="600" height="513" alt="Fig. 83." title="" />
+<span class="caption"><span class='smcap'>Fig. 83.</span>&mdash;Sawdust purifier.</span>
+</div>
+
+<p><b>Washing and Purifying.&mdash;</b>In pressure producers the gas is generally
+washed and purified with much more care than in suction apparatus. Given
+a sufficient pressure, the gas can be driven through the different
+apparatus and the spaces between the material which they contain without
+any difficulty. The gases emerge from the generator highly heated, and
+this heat is used either to warm the injection water or to generate the
+steam fed to the furnace. The gases then enter the
+<!--185.png--><span class='pagenum'><a name="Page_185" id="Page_185">[185]</a></span> washing apparatus,
+which most frequently consists of a succession of contrivances in which
+the gas is washed either by causing it to bubble up through the water,
+or by subjecting it to superficial friction against a sheet of water, or
+by systematically circulating it in a mass of continuously besprinkled
+inert material. The object of washing is to remove the dust contained in
+the gas and to precipitate it in the form of a slime which can be
+removed by flushing.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_084.jpg" width="600" height="474" alt="Fig. 84." title="" />
+<span class="caption"><span class='smcap'>Fig. 84.</span>&mdash;Moss or fiber purifier.</span>
+</div>
+
+<p>Physical purification thus begun is completed by passing the gas through
+a filtering bed consisting of fiber, sawdust, or moss (Figs. 83 and 84).
+Chemical purification if it is necessary, is effected by means of
+calcium hydrate, iron oxide, or, still better, by a mixture of lime and
+iron sulphate. This filtering material must necessarily be renewed after
+it is exhausted.
+<!--186.png--><span class='pagenum'><a name="Page_186" id="Page_186">[186]</a></span></p>
+
+<div class="figcenter" style="width: 369px;">
+<img src="images/fig_085.jpg" width="369" height="600" alt="Fig. 85." title="" />
+<span class="caption"><span class='smcap'>Fig. 85.</span>&mdash;Combined gas-holder and washer.</span>
+</div>
+
+<p><b>Gas-Holder.&mdash;</b>The gas-holder is composed essentially of a tank and a
+bell. Sometimes, for the purpose of simplifying the apparatus, the tank
+is so arranged as to take the place of a washer or scrubber (Fig. 85).
+The bell should be provided with mechanism which, when the bell is full,
+automatically diminishes or stops the generation of gas. It is advisable
+to provide the
+<!--187.png--><span class='pagenum'><a name="Page_187" id="Page_187">[187]</a></span> bell with a blow or flap valve opening toward the
+interior. If, therefore, it should happen that the gas supply is cut off
+while the engine still continues to run, the suction of the engine will
+not draw the water from the tank of the gas-holder.</p>
+
+<p>When engines are employed the horse-power of which does not exceed 50,
+it is sometimes customary to use the water of the tank (placed at a
+higher elevation than the engine) to cool the cylinder. In this manner
+the cost of installing special reservoirs is saved. If such an
+arrangement be employed, however, the quantity of water contained in the
+tank should be at least double that ordinarily contained in reservoirs.
+If this precaution be not observed, the water may become excessively
+heated and expand the gas in the bell.</p>
+
+<p>The volume of the bell of the gas-holder should preferably be not less
+than about 3 cubic feet per effective horse-power of the engine to be
+supplied. Under these circumstances the bell acts as a
+pressure-regulator, assures a sufficient homogeneity of the remaining
+gas, and renders it possible to supply the engine during the short
+intervals in which it is necessary to stop the blast to poke the fire.
+But if the engine consumes 60 to 80 cubic feet of producer-gas per
+horse-power per hour, the bell must be very much larger in size if the
+generation of gas is to be checked for some time.</p>
+
+<p>It may be well to recall here that coal is not the only fuel which lends
+itself to the generation of gas suitable for driving engines, but that
+some generators are able to utilize lignite, peat, and the like. In
+others, straw,
+<!--188.png--><span class='pagenum'><a name="Page_188" id="Page_188">[188]</a></span> wood, shavings and sawdust, tannery waste, and other
+organic matter is burnt with an efficiency very much higher than that
+which they would give in the fireboxes of steam-boilers.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_086.jpg" width="600" height="337" alt="Fig. 86." title="" />
+<span class="caption"><span class='smcap'>Fig. 86.</span>&mdash;Otto Deutz lignite-producer.</span>
+</div>
+
+<p><b>Lignite and Peat Producers.&mdash;</b>Lignite and peat generators (Fig. 86)
+cannot operate on the suction principle because of the resistance
+offered to the passage of gas by the layer of fuel. This resistance is
+considerable and extremely variable. Consequently, lignite and peat
+generators must operate on the pressure principle by utilizing a blast
+of air or a steam injector, depending upon the amount of water contained
+in the lignite. As a general rule a Root blower operating at a pressure
+of 8 to 27 inches of water, depending upon the quality of the lignite,
+is employed. These generators are not to be recommended for powers less
+than 50 horse-power, for the cost of the apparatus becomes too great.
+<!--189.png--><span class='pagenum'><a name="Page_189" id="Page_189">[189]</a></span></p>
+
+<p>The best lignite is that which, after combustion, leaves a fine ash and
+no agglomerated clinker. Lignite has the peculiarity of forming dust
+which ignites very easily when air is admitted into the generator. For
+this reason the generator should not be scraped during operation, in
+order to avoid the production of a flame which may escape from the
+apparatus.</p>
+
+<p>The scrubber is simply a column without coke, and is provided with an
+interior sprinkler. The coke is too rapidly clogged with tar. Much of
+this tar is deposited in a chamber which precedes the gas-holder.
+Several quarts of tar may be tapped from the chamber daily.</p>
+
+<p>The gas-holder serves merely to regulate the production of gas. The
+pipes leading to the engine should be cleaned several times each month,
+in order to remove the thin layer of tar which is deposited within them.</p>
+
+<p>There are many kinds of lignite, and the gas-generator should be
+constructed to meet the peculiar requirements of the variety employed.
+The layer of fuel should be such in thickness that the gas as it emerges
+from the generator has a temperature of about 77 degrees F. This is the
+temperature of the gas which leaves the scrubber in the case of
+anthracite-generators. If the lignite contains much water, the greater
+part is retained in the washer by the gas in the form of drops.
+Sometimes the water drips through the grate of the generator.
+Lignite-generators may also be operated with peat, and even with town
+refuse, with slight modifications.
+<!--190.png--><span class='pagenum'><a name="Page_190" id="Page_190">[190]</a></span>
+The consumption per horse-power per
+hour is 3.3 pounds of lignite containing 2,400 calories (9,424.9
+B.T.U.). In order to generate the same power with a boiler and
+steam-engine, 8.8 pounds would be required. An engine driven unloaded
+with fuel furnished by a lignite-generator will consume 50 per cent. of
+the weight of the fuel required at full load. This depends upon the
+proportion of water contained in the lignite and on losses of heat by
+radiation from the generator. In street-gas engines running without
+load, the absorption is 20 per cent., in anthracite-generators 40 per
+cent. of the consumption at full load.</p>
+
+<p>Passing now to the utilization of wood, of which something has already
+been said in Chapter XI, two entirely distinct processes are
+successfully employed in apparatus of the Rich&eacute; type, these processes
+depending upon the form of the wood used&mdash;whether, in other words, the
+wood be consumed in the form of sticks or blocks or in the form of
+chips, sawdust, bark, and the like, all of them the wastes of factories
+in which wood is used.</p>
+
+<p><b>Distilling-Producers.&mdash;</b>If the wood consists of logs, it is burnt in a
+generator comprising a fire-box and a distilling retort. The fire-box is
+charged with ordinary coal which serves to heat the retort to redness.
+The wood is discharged through the top of the retort, and the gas,
+produced by the distillation, escapes through the bottom and passes to
+the washing apparatus. The base of the retort is heated to about 1,652
+degrees F., while at the top this temperature is reduced to 752 degrees
+<!--191.png--><span class='pagenum'>191</span>
+F. The wood thus treated is transformed into charcoal, which is a
+by-product of some value.</p>
+
+<div class="figcenter" style="width: 330px;">
+<img src="images/fig_087.jpg" width="330" height="600" alt="Fig. 87." title="" />
+<span class="caption"><span class='smcap'>Fig. 87.</span>&mdash;Rich&eacute; distilling-producer.</span>
+</div>
+
+<p>The lower part of this cast retort (Fig. 87) is lined with charcoal, the
+residue of previous distillations. The wood which is introduced in the
+upper part of the retort is distilled in the chamber. The retort is held
+by its own weight in a socket on the foot, which socket is lined with a
+special refractory cement, made of silicate, asbestos forming the joint.
+The products
+<!--192.png--><span class='pagenum'><a name="Page_192" id="Page_192">[192]</a></span>
+of combustion, issuing from the furnace, pass by way of
+the flue to the lower part of the casing, and raise the temperature of
+the retort and the charcoal it contains to that of a cherry red (1,652
+degrees F.). These products of combustion then float to the upper part
+of the casing and heat the top of the retort to a temperature of about
+752 degrees F., in which part the wood or the wooden waste to be
+distilled is enclosed. Thence the products of combustion pass through a
+horizontal flue, provided with a damper, into a collecting flue by which
+they are led to the smoke-stack. The products of distillation formed in
+the chamber, having no outlet at the top of the retort, must traverse
+the zone filled with incandescent carbon. The condensible products are
+conducted as permanent gases (carbonic-acid gas in the state of carbon
+monoxide) and are collected in the receptacle, after having passed the
+funnel and the bell of the purifying apparatus.</p>
+
+<p>A gas-furnace is formed by grouping in a single mass of masonry a
+certain number of elements of the kind just described. It is essential
+that the retorts should be vertically placed, that they be made only of
+cast metal and not of refractory clay, and, finally, that their diameter
+be not much more than 10 inches, which size has been found most
+expedient in practice. The gas collected in the bell or in one or more
+of the receptacles passes into the gasometer and then into the service
+pipes. If 2.2 pounds of wood be distilled by burning in the furnace <sup>8</sup>&frasl;<sub>9</sub>
+of a pound of coal of average quality or 2.2 pounds of wood (either
+sawdust or waste), 24.5 to 28
+<!--193.png--><span class='pagenum'><a name="Page_193" id="Page_193">[193]</a></span>
+cubic feet of gas will be generated
+having a thermal value of 3,000 to 3,300 calories per cubic meter
+(11,904 to 13,094 B.T.U. per 35.31 cubic feet), and a residue 44 pounds
+of charcoal will be left.</p>
+
+<p>In practice only the wood of commerce containing in the green state 20
+to 40 per cent. of water, depending upon the variety, is used. Hornbeam
+contains the least water (18 per cent.), while elmwood and spruce
+contain the most (44 to 45 per cent.).</p>
+
+<p>The blast apparatus of the generator being started, the gas is supplied
+under pressure. By reason of its permanent composition and its richness,
+it is an excellent substitute for street-gas in incandescent lighting, a
+good furnace fuel reducing agent.</p>
+
+<p><i>Producers Using Wood Waste, Sawdust, and the Like.&mdash;</i>If waste wood in
+the form of shavings, sawdust, straw, bark, and the like, should be
+employed, a still higher efficiency is obtained with self-reducing
+generators of the Rich&eacute; type.</p>
+
+<p><i>Combustion-Generators.&mdash;</i>In combustion-generators (Fig. 88) the fuel is
+burnt and not distilled. The generator comprises two distinct elements.
+The first is the generator proper, in which the combustion takes place.
+Upon it is placed a hopper or fuel supply box. The Second element is the
+reducer, in which by an independent process the reduction of the
+carbonic-acid gas, the dissociation of the steam, and the transformation
+of the hydrocarbons takes place. The generator is provided at its base
+with a grate having oblique bars in tiers, which grate is furnished with
+a channel in which the
+<!--194.png--><span class='pagenum'><a name="Page_194" id="Page_194">[194]</a></span>
+ water for the generation of hydrogen flows. On a
+level with this grate, at the opposite side, is a flue communicating
+with the reduction column of coke. The incandescent zone of the
+generator should not extend above the level of the grate. Instead of
+passing through the layers of fresh fuel and out by way of the top, the
+gas generated flows directly into the reduction column where it heats
+the coke to incandescence. The high temperature to which the coke is
+subjected, coupled with the injection of air, effects useful reactions.
+This additional air, however, is not used if the fuel is free from all
+products of distillation.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_088.jpg" width="600" height="251" alt="Fig. 88." title="" />
+<span class="caption"><span class='smcap'>Fig. 88.</span>&mdash;Rich&eacute; combustion-producer.</span>
+</div>
+
+<p>Experience has shown that gas of 1,000 to 1100 calories per cubic meter
+(3,968 to 4,365 B.T.U. per 35.31 cubic feet), which heat content is
+necessary to develop one horse-power per hour, can be obtained with 3.96
+pounds of wood in the form of shavings and sawdust containing 30 per
+cent. of water. The corresponding quantity of coke consumed in the
+reduction column is
+<!--195.png--><span class='pagenum'><a name="Page_195" id="Page_195">[195]</a></span>
+insignificant, and may be placed at about 0.112
+pounds per horse-power per hour.</p>
+
+<p>It has been proven in actual practice that, both in the distilling and
+combustion types of apparatus, the wood, either in the green state or in
+the form of saw-mill waste, may contain as much as 60 per cent. of
+water. Either of the two systems can be operated under pressure with an
+air-blast, in which case a gas-holder and bell must be employed. The gas
+as it passes from the generator to the gas-holder is conducted through a
+cooler and washer and through a moss filter, which removes traces of the
+products that may have escaped the distillation.</p>
+
+<p><b>Inverted Combustion.&mdash;</b>With a few exceptions the pressure-generators
+which have been described, as well as suction gas-producers which will
+be later discussed, are fed with anthracite coal or with coke. They
+cannot be operated with moderately soft or bituminous coal. For this
+reason they limit the employment of producer-gas engines. Manufacturers
+have long sought generators in which any fuel whatever can be consumed.</p>
+
+<p>Among the producers which seem to overcome the objections cited to a
+certain degree, are those which are based on the principle of inverted
+combustion. These apparatus embody the ideas of Ebelmen, the products of
+distillation being decomposed by passing them over layers of
+incandescent fuel.</p>
+
+<!--196.png--><p><span class='pagenum'>196</span></p>
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_089.jpg" width="600" height="268" alt="Fig. 89." title="" />
+<span class="caption"><span class='smcap'>Fig. 89.</span>&mdash;Deschamps inverted-combustion producer.</span>
+</div>
+
+<p>Many writers place in the class of inverted combustion producers,
+apparatus of the Rich&eacute;, Thwaite, and Duff type, in which this idea is
+also carried out. Rich&eacute;
+<!--197.png--><span class='pagenum'>197</span>employs
+an independent incandescent mass to
+reduce the products of distillation of another mass. Thwaite employs two
+vessels which serve alternately as distilling retorts and reducing
+columns. Duff draws in the products of distillation for the purpose of
+blowing them under the fire. All these generators can hardly be said to
+be of the inverted combustion type.</p>
+
+<div class="figcenter" style="width: 329px;">
+<img src="images/fig_090.jpg" width="329" height="600" alt="Fig. 90." title="" />
+<span class="caption"><span class='smcap'>Fig. 90.</span>&mdash;Fang&eacute;-Chavanon inverted-combustion
+producer.</span>
+</div>
+<!--198.png--><p><span class='pagenum'><a name="Page_198" id="Page_198">[198]</a></span></p>
+
+<p>The generators of Deschamps (Fig. 89) and of Fang&eacute; and Chavanon (Fig.
+90), on the other hand, are producers in which the combustion is really
+inverted, and which are worked continuously. The air enters at the upper
+part of the retort, passes through the entire mass of fuel, carrying
+with it the distilled volatile products, and when the mixture reaches
+the incandescent zone, chemical reactions occur that result in the
+production of a gas entirely free from tar and other impurities.</p>
+
+<hr class="ChapterTopRule" />
+<!--199.png--><p><span class='pagenum'><a name="Page_199" id="Page_199">[199]</a></span></p>
+<h2><a name="CHAPTER_XIII" id="CHAPTER_XIII"></a>CHAPTER XIII</h2>
+
+<h3>SUCTION GAS-PRODUCERS</h3>
+
+<p>The high cost and the complicated nature of the pressure gas-generators
+which have just been discussed have led manufacturers to attempt in some
+other way the generation of producer-gas intended for operating motors.</p>
+
+<p>Several inventors, among whom we will mention B&eacute;nier and A. Taylor (in
+France), made some praiseworthy although not immediately very successful
+attempts to simplify the manufacture of producer-gas.</p>
+
+<p><b>Advantages.&mdash;</b>In these systems the suction occasioned by the motor itself
+has taken the place of a forced draft, produced in the generator by an
+air-injector or a fan, so that the gas, instead of being stored under
+pressure in a gas-holder, is kept in the apparatus under a pressure
+below that of the atmosphere.</p>
+
+<p>As the device for producing a draft by means of boiler pressure or of a
+fan, and the gas-holder, are dispensed with, the result is a saving,
+first in the cost of installation, consumption, and floor space.
+Furthermore, the cooler and washer are supplanted by a single scrubber.</p>
+
+<p>Manufacturers have succeeded in devising apparatus remarkable for the
+simplicity of the processes employed
+<!--200.png--><span class='pagenum'><a name="Page_200" id="Page_200">[200]</a></span> and yielding economical results
+which would never be obtained with pressure-generators employing
+gas-holders and boilers, considering that the boiler alone calls for a
+consumption of from 15 to 30 per cent. of the total amount of coal used
+for making the gas.</p>
+
+<p>The best results obtained by the author with pressure gas-producers have
+indicated a consumption of not much less than 1 to 1<sup>1</sup>&frasl;<sub>4</sub> pounds of
+anthracite per horse-power per hour at the motor, while with
+suction-generators, under similar conditions and with the same grade of
+fuel, he has repeatedly found a consumption of from <sup>9</sup>&frasl;<sub>10</sub> pounds per
+effective horse-power per hour. In either case, the gas obtained
+developed between 1,100 and 1,300 calories (4,365 and 5,158 B.T.U. per
+35.31 cubic feet) if produced from anthracite yielding from 7,500 to
+8,000 calories (29,763 to 31,746 B.T.U.) per 2.2 pounds.</p>
+
+<p>The suction apparatus will also work very well with inferior coal
+containing up to 6 to 8 per cent. of volatile matter and from 8 to 10
+per cent. of ash. This great advantage added to all the others explains
+the favorable reception which European manufacturers at once gave to
+suction-producers. The petroleum engine itself will find a serious
+competitor in the new system.</p>
+
+<p>As regards the possibility of employing suction gas generators with
+respect to the somewhat peculiar properties of the fuel, it may be said
+at the outset that coke from gas works yielding from 6,000 to 6,500
+calories (22,911 to 24,995 B.T.U.) and also charcoal are perfectly
+available.
+<!--201.png--><span class='pagenum'><a name="Page_201" id="Page_201">[201]</a></span></p>
+
+<p>One horse-power per hour is obtained with a consumption of 1.1 to 1.3
+pounds of coke.</p>
+
+<p>Blast-furnace coke may be used in case of need, but its employment is
+not to be recommended on account of the sulphides it contains, which
+sulphides, being carried along by the gas, are liable to form sulphuric
+acid with the steam, the corrosive action of which would soon destroy
+the cylinder and other important parts of the engine.</p>
+
+<p><b>Qualities of Fuel.&mdash;</b>Anthracite coal is, upon the whole, so far the best
+available fuel for generators. However, it should possess certain
+qualities which will now be briefly indicated.</p>
+
+<p>In suction gas-generators, above all, it is important that no harmful
+resistance should be opposed to the passage of the air and of the gas
+produced. It is therefore necessary to employ coal of a size that will
+answer the foregoing condition, without being too expensive.</p>
+
+<p>The size of the pieces, to a certain extent, determines the price; and
+with coal of the same properties, pieces 1.1 to 2 inches may cost 1.4 of
+the price for the ordinary size of 0.59 to 0.98 inches, which is very
+well adapted for gas-generators. This is the size of a hazel-nut.</p>
+
+<p>Moreover, it will be advisable to select the dryest coals, containing a
+minimum of volatile matter and having no tendency to coke or to cohere,
+in order that the volatilized products may not by distillation obstruct
+the interstices through which the gases must pass. For the same reason
+coal which breaks up and becomes pulverized
+<!--202.png--><span class='pagenum'>202</span>
+under the action of the
+fire is not to be recommended. The coal should also be such as to avoid
+the formation of arches which would interfere with the proper settling
+of the fuel during its combustion. It may be stated as a rule that, with
+coal that does not cohere, the content of volatile matter should not
+exceed 5 to 8 per cent.</p>
+
+<p>Coal which contains more than 10 to 15 per cent. of ash should not be
+used, for the reason that it chokes up and obstructs generators in which
+the dropping and discharge of the ashes is done automatically, a fact
+which should not pass unnoticed. The furnace cannot be cleaned safely
+with a fire of this kind, where combustion takes place in an enclosed
+space, without hindering the production of gas. Here again a point may
+be raised very much in favor of suction gas-producers. In a good
+generator, the ash-pit can be cleaned and the fire stoked without
+interrupting the liberation of the gas drawn in and without appreciably
+impairing the quality of the gas. These considerations are of importance
+so far as the gas-generator itself is concerned. Other conditions which
+should be noticed affect the engine fed by the generator, the grade of
+coal used, and the purification of the gas obtained from it.</p>
+
+<p>Unless special chemical cleaners and purifiers are employed, thereby
+complicating the plant, the coal utilized should yield as little tar as
+possible during distillation; for the tendency of the tar to choke up
+the pipes and to clog the valves is one of the chief causes of defective
+operation of producer-gas engines.
+<!--203.png--><span class='pagenum'><a name="Page_203" id="Page_203">[203]</a></span></p>
+
+<p>Tar changes the proper composition of the explosive mixture. When it
+catches fire in the cylinder it causes premature ignition, which is so
+dangerous in large engines.</p>
+
+<p>From what has been said in the foregoing, it follows that, in the
+present state of the art, the satisfactory operation of gas-generators
+depends no longer on the use of pure anthracite, such as Pennsylvania
+coal in America and Welsh coal in England, containing an amount of
+carbon as high as 90 to 94 per cent. and having a thermal value of
+33,529 B.T.U. On the contrary, good dry coal yielding from 29,763 to
+31,746 B.T.U. is quite suitable for the generation of producer-gas.</p>
+
+<p>A final, practical advantage which speaks in favor of a generator and
+motor plant as compared with a steam-engine, is the small amount of
+water required. Apart from the water used for cooling the engine, which
+may be used over and over again if cooled, any water, whether it forms
+scale or deposits, may be employed for cooling and washing the gas in
+the scrubber.</p>
+
+<p>According to the author's personal experience, an average of 3.3 gallons
+of water per effective horse-power per hour is sufficient for this
+purpose. This is about one-half of the amount required by a
+non-condensing slide-valve engine of from 15 to 30 horse-power. The
+difference in the consumption of water is quite important in city
+plants, where water is rather expensive as a rule.</p>
+
+<p><b>General Arrangement.&mdash;</b>A suction gas-generator
+<!--204.png--><span class='pagenum'><a name="Page_204" id="Page_204">[204]</a></span>
+plant of the character we
+have been discussing is shown in Fig. 91.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_091.jpg" width="600" height="264" alt="Fig. 91." title="" />
+<span class="caption"><span class='smcap'>Fig. 91.</span>&mdash;Engine and suction gas-producer.</span>
+</div>
+
+<p>The apparatus <i>A</i> is the generator proper, in which combustion takes
+place. The gas produced passes into the apparatus <i>B</i> through a series
+of tubes, to be conveyed to the washer <i>C</i>. In the apparatus <i>B</i>, which
+is the vaporizer, the water admitted at the top under atmospheric
+pressure is vaporized by contact with a series of tubes, heated by the
+gas coming from the generator. The steam, together with air, is drawn
+into the lower part of the generator to support combustion. This
+vaporizer is provided with an overflow for the outlet of the water which
+has not been vaporized. The producer-gas pipe which leads from the
+vaporizer to the washer has a branch <i>D</i>, for the temporary escape to
+the atmosphere of the gas produced before and after the operation of the
+engine. In the washer, as the drawing shows, the gas enters at the
+bottom and leaves at the top to pass to the gas expansion-chamber <i>E</i>
+and thence to the motor. The gas thus passes through the body of
+<!--205.png--><span class='pagenum'><a name="Page_205" id="Page_205">[205]</a></span> coke
+in the opposite direction to the wash water, which then flows to the
+waste-pipe. The coke and the water free the gas not only from the dust
+carried along, but from the ammonia and other impurities contained in
+the gas.</p>
+
+<p>When firing the generator, a small hand ventilator <i>G</i> is used for
+blowing in air to fan the fire. The gas obtained at first, being
+unsuitable for combustion, is allowed to escape through the branch <i>D</i>.
+After injecting air for about 10 to 15 minutes, the engine can be
+started after closing the branch <i>D</i>. The suction of the engine itself
+will then gradually bring about the proper conditions for its regular
+running, and after a quarter of an hour or half an hour the gas is rich
+enough to run the engine under a full load.</p>
+
+<p>The apparatus just described is the original type, upon which many
+improvements have been made for the purpose of securing a uniform gas
+production and of diminishing the interval of time elapsing between the
+firing of the generator and the running of the engine under a full load.</p>
+
+<p>Each of the elements of this apparatus&mdash;to wit, the generator,
+vaporizer, super-heater, and washer&mdash;have been modified and improved
+more or less successfully by the manufacturers; and in order that the
+reader may perceive the merits and the drawbacks of the various
+arrangements adopted, the most important ones will be separately
+discussed.</p>
+
+<p><b>Generator.&mdash;</b>With respect to the general arrangement of parts, generators
+may be divided into two classes:
+<!--206.png--><span class='pagenum'><a name="Page_206" id="Page_206">[206]</a></span></p>
+
+<p>First.&mdash;Generators with internal vaporizers, such as the Otto Deutz and
+Wiedenfeld generators.</p>
+
+<div class="figcenter" style="width: 271px;">
+<img src="images/fig_092.jpg" width="271" height="600" alt="Fig. 92." title="" />
+<span class="caption"><span class='smcap'>Fig. 92.</span>&mdash;Old type of Winterthur producer.</span>
+</div>
+
+<p>Second.&mdash;Generators with external vaporizers, such as the Taylor,
+Bollinckx, Pintsch, Kinderlen, Benz, Wiedenfeld, Hille, and Goebels
+generators.
+<!--207.png--><span class='pagenum'><a name="Page_207" id="Page_207">[207]</a></span></p>
+
+<p><b>Cylindrical Body.&mdash;</b>The generator consists essentially of a mantle made
+of sheet-iron or cast-iron and containing a refractory lining which
+forms a retort, a grate, and an ash-pit. In the small size apparatus the
+cast-iron mantle is often used, whereas in large sizes the mantle is
+made of riveted sheet-iron so as to reduce its weight and its cost. In
+the latter case the linings are securely riveted or bolted.</p>
+
+<p>The Winterthur generator (Figs. 92 and 93), the Taylor generator (Fig.
+94), and the Benz generator (Fig. 97), are made of cast-iron; the
+Wiedenfeld generator (Fig. 95), the Pintsch generator (Fig. 96), are
+made of sheet-iron; the Bollinckx (Fig. 98) is made partly of sheet-iron
+and partly of cast-iron.</p>
+
+<p>The different parts of a generator, if made of sheet-iron, are held
+together by means of angle-irons forming yokes, and a sheet of asbestos
+is interposed. If the parts are made of cast-iron, they are connected
+after the manner of pipe-joints and packed with compressed asbestos.
+This latter way of assembling the parts presents the advantage of
+allowing them to be dismembered readily. Therefore, it allows the
+several parts to expand freely and facilitates the securing of tight
+joints. This last consideration is exceedingly important, particularly
+for the joints which are beyond the zone in which the distillation of
+the fuel takes place. Any entrance of air through these joints would
+necessarily impair the quality of the gas, either by mingling therewith,
+or by combustion. The air so admitted would also be liable to form an
+explosive mixture which might
+<!--208.png--><span class='pagenum'>208</span> become ignited in case of a premature
+ignition of the cylinder charge during suction or through some other
+cause.</p>
+
+<div class="figcenter" style="width: 374px;">
+<img src="images/fig_093.jpg" width="374" height="600" alt="Fig. 93." title="" />
+<span class="caption"><span class='smcap'>Fig. 93.</span>&mdash;New type of Winterthur producer.</span>
+</div>
+<!--209.png--><p><span class='pagenum'>209</span></p>
+
+<div class="figcenter" style="width: 297px;">
+<img src="images/fig_094.jpg" width="297" height="600" alt="Fig. 94." title="" />
+<span class="caption"><span class='smcap'>Fig. 94.</span>&mdash;The A. Taylor producer.</span>
+</div>
+
+<div class="figcenter" style="width: 308px;">
+<img src="images/fig_095.jpg" width="308" height="600" alt="Fig. 95." title="" />
+<span class="caption"><span class='smcap'>Fig. 95.</span>&mdash;Wiedenfeld producer.</span>
+</div>
+
+<div class="figcenter" style="width: 276px;">
+<img src="images/fig_096.jpg" width="276" height="600" alt="Fig. 96." title="" />
+<span class="caption"><span class='smcap'>Fig. 96.</span>&mdash;Pintsch producer.</span>
+</div>
+<!--210.png--><p><span class='pagenum'>210</span></p>
+
+<div class="figcenter" style="width: 266px;">
+<img src="images/fig_097.jpg" width="266" height="600" alt="Fig. 97." title="" />
+<span class="caption"><span class='smcap'>Fig. 97.</span>&mdash;Benz producer.</span>
+</div>
+
+<div class="figcenter" style="width: 514px;">
+<img src="images/fig_098.jpg" width="514" height="600" alt="Fig. 98." title="" />
+<span class="caption"><span class='smcap'>Fig. 98.</span>&mdash;Bollinckx producer.</span>
+</div>
+<!--211.png--><p><span class='pagenum'><a name="Page_211" id="Page_211">[211]</a></span></p>
+
+<div class="figcenter" style="width: 305px;">
+<img src="images/fig_099.jpg" width="305" height="600" alt="Fig. 99." title="" />
+<span class="caption"><span class='smcap'>Fig. 99.</span>&mdash;Lencauchez producer.</span>
+</div>
+
+<p><b>Refractory Lining.&mdash;</b>The interior lining of the generator should be made
+of refractory clay of the best quality. It would seem advisable, in
+order to facilitate repairs, to employ retorts made of pieces held
+together instead of retorts made of a single piece. In the first case
+the assembling should preferably be made by means of refractory cement,
+and the inner surface
+<!--212.png--><span class='pagenum'><a name="Page_212" id="Page_212">[212]</a></span>
+should be covered with a coating so as to form a
+practically continuous stone surface.</p>
+
+<div class="figcenter" style="width: 426px;">
+<img src="images/fig_100.jpg" width="426" height="600" alt="Fig. 100." title="" />
+<span class="caption"><span class='smcap'>Fig. 100.</span>&mdash;Goebels producer.</span>
+</div>
+
+<p>Some manufacturers, in order to allow for the renewal of the part most
+liable to be burnt, employ at the bottom of the tank a refractory
+moulded ring (Lencauchez, Fig. 99).</p>
+
+<p>It is always advisable to place between the shell or
+<!--213.png--><span class='pagenum'>213</span> mantle of the
+generator and the refractory lining a layer of a material which is a bad
+conductor of heat as, for instance, asbestos or sand, in order to avoid
+as much as possible loss of heat due to external radiation (Fig. 100).</p>
+
+<div class="figcenter" style="width: 399px;">
+<img src="images/fig_101.jpg" width="399" height="600" alt="Fig. 101." title="" />
+<span class="caption"><span class='smcap'>Fig. 101.</span>&mdash;Pierson producer.</span>
+</div>
+<!--214.png--><p><span class='pagenum'><a name="Page_214" id="Page_214">[214]</a></span></p>
+
+<p><b>Grate and Support for the Lining.&mdash;</b>These parts,
+owing to their contact with the ashes and the hot embers,
+are liable to deteriorate rapidly. It is therefore
+indispensable that they should be removable and easily
+accessible, so that they may be renewed in case of need.
+From this point of view, grates composed of independent
+bars would appear to be preferable. The
+clearance between the bars depends, of course, on the
+kind of ashes resulting from the different grades of
+fuel. It is advisable to design the grate so that the free
+passage for the air is about 60 to 70 per cent. of the
+total surface.</p>
+
+<p>In generators having a cup-shaped ash-pit, containing
+water (Fig. 95), the grate and the base of the retort
+are less liable to burn than in apparatus having dry
+ash-pits. Certain apparatus, such as those of Lencauchez
+(Fig. 99), Pierson (Fig. 101), and Taylor (Fig.
+94), have no grates; the fuel is held in the retort by the
+ashes, which form a cone resting on a sheet-iron base,
+easy of access for cleaning and from which the fuel
+slides down gradually.</p>
+
+<p>The Pierson generator (Fig. 101) is provided with
+a poker comprising a central fork, which is worked
+with a lever, in order to stir the fire from below without
+entirely extinguishing the cone of ashes.</p>
+
+<p>In some apparatus in which a grate is used (Fig. 92),
+a space is left between the grate and the support of the
+retort. This arrangement has the merit of allowing
+only finely divided and completely burnt ashes to pass
+to the ash-pit. Moreover, a large surface grate can be
+<!--215.png--><span class='pagenum'><a name="Page_215" id="Page_215">[215]</a></span>
+employed, thus facilitating the passage of the mixture
+of air and steam.</p>
+
+<div class="figcenter" style="width: 385px;">
+<img src="images/fig_102.jpg" width="385" height="600" alt="Fig. 102." title="" />
+<span class="caption"><span class='smcap'>Fig. 102.</span>&mdash;Kiderlen producer.</span>
+</div>
+
+<p>The space above mentioned is provided with a cleaning-door
+through which cinder and slag may be removed.</p>
+
+<p>In other apparatus the grate rests either on the support
+of the refractory lining, as in the old type invented
+<!--216.png--><span class='pagenum'><a name="Page_216" id="Page_216">[216]</a></span></p>
+
+<p>by Wiedenfeld (Fig. 95), or upon a projection embedded
+in the lining, as, for instance, in the Kiderlen
+(Fig. 102) and Pintsch generators (Fig. 96).</p>
+
+<p>In the Rich&eacute; apparatus (Fig. 103) there is, besides
+the ordinary grate, a grate with tiers on which the fuel
+spreads. This grate consists of wide, hollow bars containing
+water. It should be noted that the apparatus is
+of the blower type.</p>
+
+<div class="figcenter" style="width: 594px;">
+<img src="images/fig_103.jpg" width="594" height="600" alt="Fig. 103." title="" />
+<span class="caption"><span class='smcap'>Fig. 103.</span>&mdash;Rich&eacute; combustion-producer.</span>
+</div>
+
+<p>An interesting arrangement is found in B&eacute;nier's generator
+(Fig. 104). This consists of a grate formed of
+projections cast around a cylinder which can be turned
+about its axis. The finely divided ashes which are retained
+<!--217.png--><span class='pagenum'><a name="Page_217" id="Page_217">[217]</a></span>
+in the spaces between these projections are thus
+carried into the ash-pit, and those which adhere to the
+metal are scraped away by a metallic comb fastened to
+the lower part of the apparatus. The "Ph&#339;nix" generator
+(Fig. 105) is fitted with a grate having a
+mechanical cleaning device, worked by a lever from the
+outside.</p>
+
+<div class="figcenter" style="width: 315px;">
+<img src="images/fig_104.jpg" width="315" height="600" alt="Fig. 104." title="" />
+<span class="caption"><span class='smcap'>Fig. 104.</span>&mdash;B&eacute;nier producer.</span>
+</div>
+
+<!--218.png--><p><span class='pagenum'>218</span></p>
+<div class="figcenter" style="width: 323px;">
+<img src="images/fig_105.jpg" width="323" height="600" alt="Fig. 105." title="" />
+<span class="caption"><span class='smcap'>Fig. 105.</span>&mdash;Ph&#339;nix producer.</span></div>
+
+<p><b>Ash-Pit.&mdash;</b>The ash-pits are exposed to the destructive
+<!--219.png--><span class='pagenum'>219</span>
+effects of heat and moisture, and should preferably be
+constructed of cast-iron, since sheet-steel is liable to
+corrode quickly.</p>
+
+<div class="figcenter" style="width: 411px;">
+<img src="images/fig_106.jpg" width="411" height="600" alt="Fig. 106." title="" />
+<span class="caption"><span class='smcap'>Fig. 106.</span>&mdash;Otto Deutz producer.</span>
+</div>
+
+<p>In most apparatus the ash-pit is hermetically sealed,
+and the air for supporting combustion enters below the
+<!--220.png--><span class='pagenum'><a name="Page_220" id="Page_220">[220]</a></span>
+grate through a pipe leading from the heater or the
+vaporizer. This arrangement seems best adapted to
+prevent the leakage of gas which tends to take place by
+reaction after each suction stroke of the engine.</p>
+
+<p>Ash-pits formed as water-cups, such as the Deutz
+(Fig. 106), the Wiedenfeld (Fig. 95), and the Bollinckx
+(Fig. 98), are fed by the overflow from the
+vaporizer. These ash-pits are themselves provided
+with an overflow consisting of a siphon-tube forming a
+water-seal.</p>
+
+<p>Besides providing protection to the grate and other
+parts by this sheet of water, a larger proportion of the
+heat radiated from the furnace is utilized for the production
+of steam which contributes to enrich the gas.
+The doors of the ash-pits and their fittings are likewise
+exposed to a rapid deterioration.</p>
+
+<p>For this reason these parts should be very strongly
+made, either of cast-iron or cast-steel. Furthermore,
+they should, at joint surfaces, be connected in an air-tight
+manner, which may be attained by carefully finishing
+the engaging surfaces of the frame and the door
+proper, or by cutting a dovetail groove in one of the
+sides of the frame which is packed with asbestos and
+adapted to receive a sharp edged rib on the other part.</p>
+
+<p>The pintles of the hinges should also be carefully
+adjusted so that the joint members of the door shall remain
+true. Hinges with horizontal axes seem to be
+preferable in this respect to those having vertical axes.
+As a means of closing the door, the arrangement here
+shown (Fig. 107) seems to assure a proper engagement
+<!--221.png--><span class='pagenum'><a name="Page_221" id="Page_221">[221]</a></span>
+of the joint surfaces. It consists of a yoke which straddles
+the door, and which, on the one hand, swings about the
+hinge, and on the other hand engages a movable
+hoop. A screw, fastened to the yoke, serves to tighten
+the door by pressure on its center. This screw can also
+be fastened to the end of the yoke (Fig. 108).</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_108.jpg" width="600" height="242" alt="Fig. 109." title="" />
+<span class="caption"><span class="smcap">Figs. 107-108.</span>&mdash;Fire-box doors.</span>
+</div>
+
+<p>It is very advantageous to provide in each door a
+hole closed by an air-tight plug, so that in case of
+need a tool may be introduced for cleaning the grate.
+In this manner the grate may be cleaned without
+opening doors and without causing a harmful entrance
+of air.</p>
+
+<p>The door of the furnace, particularly, should be provided
+with an iron counter-plate held by hinged bolts
+(Fig. 109); or, better still, this door should be so constructed
+that it can be lined with refractory material to
+protect it against the radiated heat of the fire.</p>
+
+<p><b>Charging-Box.&mdash;</b>Like the other parts of the generator
+the construction of which has been discussed above,
+the charging-box should be absolutely air-tight.
+<!--222.png--><span class='pagenum'><a name="Page_222" id="Page_222">[222]</a></span></p>
+
+<p>On account of their greater security, preference
+should be given to double closure devices, which form
+a sort of preliminary chamber, owing to which the filling
+of the generator is made in two operations. The
+first operation consists in filling the preliminary chamber
+after opening the outer door. Upon closing this
+outer door, the second operation is performed, which
+consists in moving the inner door so as to cause the fuel
+in the preliminary chamber to drop into the generator.
+Stress has been laid on the greater safety of this type of
+charging-box for the reason that, with devices having a
+single charging-door, a sudden gust of air may rush
+in at the time of charging the furnace, and bring about
+an explosion very dangerous to the workman entrusted
+with stoking the furnace.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_109.jpg" width="600" height="248" alt="Fig. 109." title="" />
+<span class="caption"><span class='smcap'>Fig. 109.</span>&mdash;Door with refractory lining.</span>
+</div>
+
+<p>The closure is generally simply a removable cover,
+or may be a lid swinging about a hinge having a horizontal
+or vertical axis.</p>
+
+<p>As regards the inner door, which is of great importance,
+in order to insure an air-tight joint, there are
+three chief types of closure:
+<!--223.png--><span class='pagenum'><a name="Page_223" id="Page_223">[223]</a></span></p>
+
+<ul><li>1. The Lift-Valve.</li>
+<li>2. The Slide-Valve.</li>
+<li>3. The Cock.</li></ul>
+
+<p><b>The Lift-Valve.&mdash;</b>The lift-valve is formed by a disk
+of conical or spherical shape moved up and down by
+means of a lever having a counter-weight for adjustment.
+The valve is used in the Winterthur (Fig. 92)
+and Bollinckx (Fig. 98) generators.</p>
+
+<p>This device serves as an automatic closure and insures
+a tight joint irrespective of wear. Moreover, it presents
+the advantage that, at the moment of opening, it distributes
+the fuel evenly in the generator; but on the
+other hand, it has the drawback of not allowing the
+fuel to be examined or shaken through the charging-box.
+In apparatus provided with this kind of valve, it
+is therefore advisable to furnish the upper part of the
+generator with agitating holes closed by an air-tight
+slide.</p>
+
+<p><b>Slide-Valve.&mdash;</b>The slide-valve closure consists of a
+smooth-finished metallic plate movable below the
+charging-box proper. Operated as it is from the outside,
+it is evident that the slightest play, the wearing of
+the pivot, or the weight of the charge, will form spaces
+between the plate and its seat through which air may
+rush in.</p>
+
+<p>Furthermore, the manipulation of the slide-valve
+may be interfered with if too much fuel is put in the
+generator.</p>
+
+<p>The valve or damper may move parallel to itself or
+swing about the operating axis. The Taylor apparatus
+<!--224.png--><span class='pagenum'><a name="Page_224" id="Page_224">[224]</a></span>
+(Fig. 94) and the B&eacute;nier apparatus (Fig. 104) are
+provided with such valves.</p>
+
+<p>The Pintsch generator (Fig. 96) is provided with a
+device which, properly speaking, is not a damper, but
+which consists of two boxes movable about a vertical
+axis and arranged to be displaced alternately above the
+shaft to effect the charging. This system effects only
+a single closure, but explosions are scarcely to be feared
+with an apparatus of this kind, owing to the considerable
+height of fuel contained between the charging
+opening and the gas-producing zone.</p>
+
+<p><b>Cock.&mdash;</b>The cock is applied particularly in the modern
+apparatus of the Otto Deutz Co. (Fig. 106) and
+the Pierson generator (Fig. 101). It consists of a large
+cast-iron cone, having an operating handle and an
+opening. The cone moves in a sleeve formed by the
+charging-box.</p>
+
+<p>This arrangement appears to be preferable to the
+others on account of its simplicity and of the ease with
+which it can be taken apart for cleaning. Moreover,
+the fuel can be poked directly through the feed-hopper.
+In apparatus provided with a cock, it is advisable to
+place on the outside cover a mica pane through which
+the condition of the fuel may be examined without
+danger.</p>
+
+<p><b>Feed-Hopper.&mdash;</b>Below the charging-box is arranged,
+as a rule, a hopper tapered conically downward. This
+part of the generator should serve only as a storage
+chamber for fuel. It can therefore be made of cast-iron,
+and has the advantage of being removable, easily
+<!--225.png--><span class='pagenum'><a name="Page_225" id="Page_225">[225]</a></span>
+replaced, and of allowing ready access to the retort for
+the purposes of examination and repair.</p>
+
+<p>The annular space surrounding this feed-hopper generally
+forms a chamber for receiving the gas produced,
+as in the Winterthur (Fig. 92), the Bollinckx (Fig.
+98), and the Taylor apparatus (Fig. 99).</p>
+
+<p>In generators having an internal vaporizing-tank,
+this tank itself serves as a feed-hopper, which is the
+case in the Deutz apparatus (Fig. 106) and Wiedenfeld
+generator (Fig. 95).</p>
+
+<p><b>Connection of Parts.&mdash;</b>In order to facilitate the
+thorough cleaning of the retort, preference is given to
+removable charging-boxes and feed-hoppers. These
+are features of apparatus of the Bollinckx type (Fig.
+98), in which the charging-box is secured to the generator
+by means of its yoke and by catches provided
+with knobs, and also of apparatus of the Winterthur
+kind (Fig. 92), having a charging-box pivoted about
+a vertical axis, or apparatus of the Duplex type (Fig.
+110), in which the charging-box can swing about a
+horizontal hinge.</p>
+
+<p><b>Air Supply.&mdash;</b>We have seen that, when starting the
+generator, the gas is produced with the aid of a fan.
+This fan may be operated mechanically, but is generally
+operated by hand.</p>
+
+<p>It is customary to convey the air-blast through a pipe
+leading to the ash-pit, as in the Winterthur apparatus
+(Fig. 92). Often, however, the air supply pipe is directly
+branched on that which leads from the vaporizer
+to the ash-pit, as in the Deutz apparatus (Fig.
+<!--226.png--><span class='pagenum'><a name="Page_226" id="Page_226">[226]</a></span>
+106). In this case a set of valves or dampers permits
+the disconnection of the fan or its connection with the
+ash-pit.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_110.jpg" width="600" height="529" alt="Fig. 110." title="" />
+<span class="caption"><span class='smcap'>Fig. 110.</span>&mdash;Duplex charging-hopper.</span>
+</div>
+
+<p>In some apparatus an air inlet is provided immediately
+adjacent to the ash-pit. This arrangement is
+faulty for the reason that it gives rise to gaseous emanations
+which take place by reaction after each suction
+stroke of the engine. Furthermore, it is advisable that
+the air supplied below the ash-pit be as hot as possible.
+For this reason the employment of preheaters is desirable.
+The dry air forced in by the fan stimulates combustion,
+and the hot gas produced and mixed with
+smoke escapes through a separate flue, generally arranged
+beyond the vaporizer and serving as a chimney.
+This chimney should in all cases be extended to the
+outside of the building, and should never terminate in
+<!--227.png--><span class='pagenum'>227</span>
+a brick chimney or similar smoke-flue. The direct
+escape of such gas and smoke through a telescopic
+chimney above the charging-box has been generally
+abandoned in modern structures.</p>
+
+<div class="figcenter" style="width: 262px;">
+<img src="images/fig_111.jpg" width="262" height="600" alt="Fig. 111." title="" />
+<span class="caption"><span class='smcap'>Fig. 111.</span>&mdash;Bollinckx flue
+and scrubber.</span>
+</div>
+
+<div class="figcenter" style="width: 175px;">
+<img src="images/fig_112.jpg" width="175" height="600" alt="Fig. 112." title="" />
+<span class="caption"><span class='smcap'>Fig. 112.</span>&mdash;Winterthur flue
+and air-reheater.</span>
+</div>
+<!--228.png--><p><span class='pagenum'><a name="Page_228" id="Page_228">[228]</a></span></p>
+
+<p>The escape-pipe mentioned, being branched on the
+gas-pipe leading to the engine, should be capable of
+disconnection when desired, by a thoroughly tight system
+of closure. For this purpose, some employ a simple
+cock (Bollinckx, Fig. 111), a three-way cock, a set of
+cocks, or, still better, a double valve, as in the Winterthur
+apparatus (Fig. 112) and the Deutz apparatus
+(Fig. 113). A double seated valve is also used, as is
+the case in the Benz generator (Fig. 114).</p>
+
+<div class="figcenter" style="width: 268px;">
+<img src="images/fig_113.jpg" width="268" height="600" alt="Fig. 113." title="" />
+<span class="caption"><span class='smcap'>Fig. 113.</span>&mdash;Otto Deutz flue.</span>
+</div>
+
+<div class="figcenter" style="width: 190px;">
+<img src="images/fig_114.jpg" width="190" height="600" alt="Fig. 114." title="" />
+<span class="caption"><span class='smcap'>Fig. 114.</span>&mdash;Benz flue.</span>
+</div>
+<!--229.png--><p><span class='pagenum'><a name="Page_229" id="Page_229">[229]</a></span></p>
+
+<p><b>Vaporizer-Preheaters.&mdash;</b>As has been stated before,
+there are vaporizers internal or external, relatively to
+the generator.</p>
+
+<p><b>Internal Vaporizers.&mdash;</b>The Deutz apparatus (Fig.
+106), for example, consists of an annular cast-iron tank
+mounted above the retort of the generator.</p>
+
+<p>The hot gases given off by the burning fuel travel
+around this tank and vaporize the water which it contains.
+The air drawn in by the suction of the engine
+enters through an opening located above the tank,
+travels over the surface of the water which is being
+vaporized, and thus laden with steam passes to the
+ash-pit.</p>
+
+<p>The tank in question is supplied with water by means
+of a cock having a sight feed, located on the outside,
+and the level is kept constant by means of an overflow
+tube leading to the ash-pit. It is well to bend this tube
+and to place a funnel on its lower member. The
+amount of overflow may thus be regulated.</p>
+
+<p>These vaporizers are simple and take up little room;
+but they are open to the apparently well-founded objection
+that they heat up slowly and require a considerable
+time to produce the steam necessary to enrich the gas,
+this being due to the relatively large mass of cast-iron
+and the amount of water contained therein.</p>
+
+<p>The Pierson vaporizer (Fig. 101) and the Chavanon
+vaporizer (Fig. 115) both consist of an annular tank
+forming the base of the generator. Steam is formed
+near the outlet of the ashes, which, as has been described
+above, leads to the outer air. The development of
+<!--230.png--><span class='pagenum'><a name="Page_230" id="Page_230">[230]</a></span>
+steam is regulated by mechanical means controlled by
+the suction of the engine.</p>
+
+<div class="figcenter" style="width: 394px;">
+<img src="images/fig_115.jpg" width="394" height="600" alt="Fig. 115." title="" />
+<span class="caption"><span class='smcap'>Fig. 115.</span>&mdash;Chavanon producer.</span>
+</div>
+
+<p><b>External Vaporizers.&mdash;</b>External vaporizers are generally
+formed by a cylinder with partitions constituting
+two series of chambers. In one of these the hot gases
+<!--231.png--><span class='pagenum'><a name="Page_231" id="Page_231">[231]</a></span>
+from the generator travel, and in the others the water to
+be vaporized is contained.</p>
+
+<div class="figcenter" style="width: 314px;">
+<img src="images/fig_116.jpg" width="314" height="600" alt="Fig. 116." title="" />
+<span class="caption"><span class='smcap'>Fig. 116.</span>&mdash;Taylor vaporizer.</span>
+</div>
+
+<div class="figcenter" style="width: 261px;">
+<img src="images/fig_117.jpg" width="261" height="600" alt="Fig. 117." title="" />
+<span class="caption"><span class='smcap'>Fig. 117.</span>&mdash;Deutz vaporizer.</span>
+</div>
+
+<p><b>Tubular Vaporizers.&mdash;</b>Different types of tubular
+vaporizers are manufactured. The vaporizer with a
+series of tubes, as in Taylor's apparatus (Fig. 116),
+Deutz's old model (Fig. 117), or with single tube like
+Pintsch's generator (Fig. 118), is formed by three compartments
+separated by two tube sheets or by plates
+which are connected by tubes.</p>
+
+<p>In some cases the gases pass within the tubes, while
+the water to be vaporized surrounds them; as in the
+<!--232.png--><span class='pagenum'><a name="Page_232" id="Page_232">[232]</a></span>
+Pintsch apparatus (Fig. 118), and Taylor apparatus
+(Fig. 116), Benz (Fig. 119), and Koerting generators
+(Fig. 120).</p>
+
+<div class="figcenter" style="width: 359px;">
+<img src="images/fig_118.jpg" width="359" height="600" alt="Fig. 118." title="" />
+<span class="caption"><span class='smcap'>Fig. 118.</span>&mdash;Pintsch vaporizer and scrubber.</span>
+</div>
+
+<p>In other cases, the water lies inside and the gas outside.
+In this latter case, a longitudinal baffle is employed
+to compel the gases to heat the tubes in their
+whole length, as in the Deutz producer (Fig. 117). In
+a general way it may be said that such a series of tubes
+<!--233.png--><span class='pagenum'><a name="Page_233" id="Page_233">[233]</a></span>
+presents the disadvantage of becoming clogged up
+rapidly by the deposit of lime salts contained in water.</p>
+
+<div class="figcenter" style="width: 250px;">
+<img src="images/fig_119.jpg" width="250" height="600" alt="Fig. 119." title="" />
+<span class="caption"><span class='smcap'>Fig. 119.</span>&mdash;Benz vaporizer.</span>
+</div>
+
+<div class="figcenter" style="width: 385px;">
+<img src="images/fig_120.jpg" width="385" height="600" alt="Fig. 120." title="" />
+<span class="caption"><span class='smcap'>Fig. 120.</span>&mdash;Koerting vaporizer.</span>
+</div>
+
+<p>If the set of tubes consists of fire-tubes, the deposit
+will form on the outer surface, that is, on a portion not
+accessible for cleaning. From this point of view,
+water-tubes are preferable, as they allow the deposit or
+scale to be removed through the tubular heads or plates.
+On the other hand, such water-tubes have the drawback
+that their exterior surfaces are readily covered
+with pitch and soot. The tubular vaporizers of the
+<!--234.png--><span class='pagenum'><a name="Page_234" id="Page_234">[234]</a></span>
+Field type (Bollinckx, Fig. 98) are composed of a
+single sheet-iron tube or shell, in which the tubes are
+arranged, dipping into a chamber through which the
+hot gases pass. This arrangement insures a rapid production
+of steam, but the Field tubes are even more
+liable than the others to become covered with deposits.</p>
+
+<p>It will be seen that these types of vaporizers should
+all present the following features: easy access, small
+quantity of the body of water undergoing vaporization,
+and large heating surface with small volume.</p>
+
+<p>The use of copper or brass tubes should be strictly
+avoided, as they would be quickly corroded by the
+action of the ammonia and hydrogen sulphide contained
+in the gas.</p>
+
+<p><b>Partition Vaporizers.&mdash;</b>Partition vaporizers comprise
+a cylindrical shell, generally made of cast-iron
+and having a double wall in which the water to be
+vaporized circulates. The gas coming from the generator
+passes into the central portion, where it comes in
+contact with a hollow baffle, also containing water
+(Wiedenfeld, Fig. 121). Vaporizers of this kind are
+strong, simple, and easily cleaned.</p>
+
+<p><b>Operation of the Vaporizers.&mdash;</b>The general purpose
+of vaporizers, whatever their construction may be,
+is to produce steam under atmospheric pressure, by
+utilizing the heat of the generator gases immediately
+after their production, or, as in the Chavanon system,
+by utilizing the heat radiated from the furnace.</p>
+
+<p>The air drawn by the engine through the generator
+generally passes through the vaporizers and becomes
+<!--235.png--><span class='pagenum'>235</span>
+laden with a certain amount of steam which it carries
+along. The amount thus taken up depends chiefly upon
+the temperature and the amount of gases coming from
+the generator, so that the greater the amount drawn into
+the engine, the more energetic will the vaporization be,
+and the richer the gas will become. It will be understood
+that when a generator is working at its maximum
+production, the interior temperature is highest and
+most favorable to the decomposition of the largest
+amount of steam.</p>
+
+<div class="figcenter" style="width: 292px;">
+<img src="images/fig_121.jpg" width="292" height="600" alt="Fig. 121." title="" />
+<span class="caption"><span class='smcap'>Fig. 121.</span>&mdash;Wiedenfeld vaporizer.</span>
+</div>
+<!--236.png--><p><span class='pagenum'><a name="Page_236" id="Page_236">[236]</a></span></p>
+
+<p>It follows that with the very simple vaporizers which
+have been reviewed, a practically automatic regulation
+is obtained. However, some manufacturers have
+deemed it advisable to regulate the amount of steam
+more accurately, and to make it exactly proportionate
+to the power developed by the motor. Thus in the
+Winterthur gas-producer (Figs. 92 and 112) the manufacturers
+have omitted the vaporizer proper, and use
+instead an air-heater and a super-heater for air and
+steam.</p>
+
+<p>The heater is formed by a cast-iron box having two
+compartments, through one of which the hot gases from
+the generator pass, while in the other the air intended
+to support combustion travels. At the inlet of the
+super-heater a pipe terminates, which feeds, drop by
+drop, water supplied by a feed device to be described
+presently. This water is vaporized immediately upon
+contact with the wall of the super-heater and is carried
+along with the air contained in it.</p>
+
+<p>The super-heater comprises a hollow ring-shaped
+cast-iron piece arranged in the chamber of the generator,
+in which the gases are developed, and is thus heated
+to a high temperature. The mixture of air and steam
+circulates in this super-heater before traveling to the
+ash-pit.</p>
+
+<p>The feeder of the Winterthur gas-generator (Fig.
+122) is composed of a receptacle having the shape of a
+tank or basin containing water and located below a
+closed cylindrical box. In this box a piston moves,
+which is provided at its lower end with a needle-valve.
+<!--237.png--><span class='pagenum'>237</span>
+The upper portion of the box communicates with the
+gas-suction pipe through a small tube. At each suction
+stroke of the engine, according to the force of the suction,
+the needle-valve piston rises more or less and thus
+allows a variable amount of water to pass.</p>
+
+<div class="figcenter" style="width: 480px;">
+<img src="images/fig_122.jpg" width="480" height="600" alt="Fig. 122." title="" />
+<span class="caption"><span class='smcap'>Fig. 122.</span>&mdash;Winterthur feeders.</span>
+</div>
+
+<p>This apparatus&mdash;and all those based on the same
+principle&mdash;presents the advantage of proportioning the
+amount of water to the work of the engine; but in view
+of its rather sensitive operation it must be kept in perfect
+repair and carefully watched. Obviously, should
+the water contain impurities, the needle-valve will bind
+<!--238.png--><span class='pagenum'><a name="Page_238" id="Page_238">[238]</a></span>
+or the orifices will be obstructed, and thus the feeding
+of the water will be interrupted. This will not only result
+in the production of a poorer gas, but will lead to
+greater wear of the grates, which in this case are not
+sufficiently cooled by the introduction of steam.</p>
+
+<div class="figcenter" style="width: 371px;">
+<img src="images/fig_123.jpg" width="371" height="600" alt="Fig. 123." title="" />
+<span class="caption"><span class='smcap'>Fig. 123.</span>&mdash;Hille producer.</span>
+</div>
+
+<p><b>Air-Heaters.&mdash;</b>The preliminary heating of the air
+appears to be of great utility for keeping up a good fire.
+This heating is very easily accomplished, and is generally
+effected by utilizing a portion of the waste heat
+of the gases, a procedure which also has the advantage
+of cooling the gases before they pass through the washing
+apparatus.
+<!--239.png--><span class='pagenum'><a name="Page_239" id="Page_239">[239]</a></span></p>
+
+<p>The heating of the air for supporting combustion
+takes place either before the addition of steam (Hille's
+generator, Fig. 123), or after the mixture as in Wiedenfeld's
+apparatus (Fig. 95). In the first case, the air
+passes through a sheet-iron shell concentric with the
+basin of the generator, is there heated by the radiated
+heat, and is conveyed to the ash-pit by a tube into which
+leads the steam-supply pipe extended from the vaporizer.
+In the second type of heater, the mixture of air
+and steam is super-heated during its passage through an
+annular piece arranged in the ash-pit of the generator.</p>
+
+<div class="figcenter" style="width: 400px;">
+<img src="images/fig_124.jpg" width="400" height="386" alt="Fig. 124." title="" />
+<span class="caption"><span class='smcap'>Fig. 124.</span>&mdash;Benz dust-collector.</span>
+</div>
+
+<p><b>Dust-Collectors.&mdash;</b>Dust-collectors are generally
+placed between the generator and the scrubber or
+washer. They may be formed of baffle-board arrangements
+against which the gases laden with dust impinge,
+causing the dust to be thrown down into a box provided
+with a cleaning opening (Benz, Fig. 124, and Pintsch,
+Fig. 118).</p>
+
+<p>Some collectors are formed either by the vaporizer
+itself, terminating at its base in a tube which dips into
+water and forms a water-seal, as in the Wiedenfeld generator
+(Fig. 121), or by a water-chamber into which
+the gas-supply tube slightly dips (Bollinckx, Fig. 111).
+<!--240.png--><span class='pagenum'><a name="Page_240" id="Page_240">[240]</a></span>
+With this arrangement, the gas will bubble through the
+water and will be partly freed of the dust suspended in
+it. These water-chambers are generally fed by the
+overflow from the spray of the scrubber. There is thus
+produced a continuous circulation by which the dust,
+in the form of slime, is carried toward the waste-pipe or
+sewer.</p>
+
+<p><b>Cooler, Washer, Scrubber.&mdash;</b>Some manufacturers
+cool the gas in a tower with water circulation. Most
+manufacturers, however, simply cool the gas in the
+washer or scrubber. This apparatus comprises a cylindrical
+body of sheet-iron or cast-iron formed of two
+compartments separated by a wooden or iron grate or
+perforated partition. The upper compartment up to
+a certain level contains either coke, glass balls, stones,
+pieces of wood, and the like. The top of the compartment
+is provided with a water supply in the nature of
+a sprinkler or spray nozzle. The lower compartment
+of the scrubber serves to collect the wash-water which
+has passed through the substance filling the tower. An
+overflow in the shape of a siphon, provided with a water
+seal, carries the water to the waste-pipe either directly
+or after it has first passed through the dust collector.</p>
+
+<p>The gas drawn in enters the washer in the lower compartment
+either above the water level (Deutz, Fig.
+125; Winterthur, Fig. 126), or through an elbow
+which dips slightly into the water (Benz, Fig. 127;
+Fichet and Heurtey producer, Fig. 128).</p>
+
+<p>The gas passes through the grate or partition which
+supports the material filling the tower, and travels
+<!--241.png--><span class='pagenum'>241</span>
+through the interstices in a direction opposite to that of
+the water falling from the top. Under these conditions,
+the gas is cooled, gives up the ammonia and the dust
+which it may still contain in suspension, and is conveyed
+to the engine either directly or after passing through
+certain purifiers. Care should be taken to place the
+<!--242.png--><span class='pagenum'><a name="Page_242" id="Page_242">[242]</a></span>
+pieces of most regular shape along the walls, so that
+the unevenness of their surfaces may not form upward
+channels along the shell, through which channels the
+gas could pass without meeting the wash-water.</p>
+
+<div class="figcenter" style="width: 242px;">
+<img src="images/fig_125.jpg" width="242" height="600" alt="Fig. 125." title="" />
+<span class="caption"><span class='smcap'>Fig. 125.</span>&mdash;Otto Deutz scrubber.</span>
+</div>
+
+<div class="figcenter" style="width: 209px;">
+<img src="images/fig_126.jpg" width="209" height="600" alt="Fig. 126." title="" />
+<span class="caption"><span class='smcap'>Fig. 126.</span>&mdash;Winterthur scrubber.</span>
+</div>
+
+<div class="figcenter" style="width: 398px;">
+<img src="images/fig_127.jpg" width="398" height="600" alt="Fig. 127." title="" />
+<span class="caption"><span class='smcap'>Fig. 127.</span>&mdash;Benz scrubber.</span>
+</div>
+
+<p>The material most commonly employed in washers is
+coke in pieces of from 2<sup>1</sup>&frasl;<sub>2</sub> to 3<sup>1</sup>&frasl;<sub>2</sub> inches in size. This
+material is cheap and is very well suited for retaining
+<!--243.png--><span class='pagenum'>243</span>
+the impurities of the gas. The largest pieces of coke
+should be placed at the bottom of the washer, and
+smaller pieces should form at the top a layer from 6 to
+8 inches deep. In this manner the water is distributed
+more evenly and the gas is more thoroughly washed.
+Blast-furnace coke is best suited for this washing, as it
+is more porous and less brittle than gas-works coke. It
+<!--244.png--><span class='pagenum'><a name="Page_244" id="Page_244">[244]</a></span>
+is advisable to put a baffle-board in front of the gas outlet
+to reduce the carrying along of water in the conduits.</p>
+
+<div class="figcenter" style="width: 289px;">
+<img src="images/fig_128.jpg" width="289" height="600" alt="Fig. 128." title="" />
+<span class="caption"><span class='smcap'>Fig. 128.</span>&mdash;Fichet-Heurtey scrubber.</span>
+</div>
+
+<div class="figcenter" style="width: 234px;">
+<img src="images/fig_129.jpg" width="234" height="600" alt="Fig. 129." title="" />
+<span class="caption"><span class='smcap'>Fig. 129.</span>&mdash;Scrubber-doors.</span>
+</div>
+
+<p>The tower of the washer should be provided with
+three openings having air-tight closures, easily fastened
+by screws (Fig. 129). One of the openings is located
+in the lower compartment, slightly above the water
+level, to allow the deposits to be removed and to permit
+the cleaning of the orifice of the gas-supply tube,
+which is particularly liable to be obstructed. The second
+opening is placed above the grating which supports
+the filtering material. The third opening is provided
+on the top of the apparatus to permit the examination
+and cleaning of the water feed device and the
+gas outlet without the necessity of taking the lid of the
+washer apart, the joint of which is kept tight with difficulty.
+The two openings last mentioned also serve for
+introducing and removing the filtering material.</p>
+
+<p><b>Purifying Apparatus.&mdash;</b>In some cases, where it is
+necessary to have very clean gas or where coal is employed
+which is softer than anthracite coal, and which
+therefore produces an appreciable amount of tar, supplementary
+purifying means must be employed. The
+apparatus for this purpose may, like the washers, be
+based upon a physical action or upon a chemical action.
+The physical action has for its purpose chiefly to retain
+the pitch and the dust which may have passed
+through the washer.</p>
+
+<p>This is accomplished by means of sawdust or wood
+shavings arranged in a thin layer and capable of filtering
+<!--245.png--><span class='pagenum'><a name="Page_245" id="Page_245">[245]</a></span>
+the gas without opposing too great a resistance to
+its passage. These materials are spread on one or more
+shelves superposed to form successive compartments in
+a box closed in an air-tight manner by an ordinary lid
+or a water seal cover (Pintsch, Fig. 130; Fichet and
+Heurtey, Fig. 131). It may be well to point out that
+the presence of the water carried along will, in the end,
+destroy the efficiency of the precipitated materials,
+because they swell up and cease to be permeable to
+the gas. These materials must therefore be renewed
+rather frequently. To obviate this drawback, vegetable
+moss may be employed, which is much less affected by
+moisture than most filters and keeps its spongy condition
+for a long time.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_130.jpg" width="600" height="491" alt="Fig. 130." title="" />
+<span class="caption"><span class='smcap'>Fig. 130.</span>&mdash;Pintsch purifier.</span>
+</div>
+
+<p>The chemical action has for its chief object to rid
+the gas of the carbonic acid and the hydrogen sulphide
+which certain fuels give off in appreciable amounts.
+<!--246.png--><span class='pagenum'><a name="Page_246" id="Page_246">[246]</a></span>
+The purifying material, in this case, is formed either
+by a mixture of hydrate of lime and natural iron oxide,
+or by the so-called Laming mass, which consists of iron
+sulphide, slaked lime, and sawdust, which last serves
+the purpose of rendering the material looser and more
+permeable to the gas. The Laming mass as well as
+other purifying materials will become exhausted in the
+course of chemical reactions. It can be regenerated
+merely by exposure to the air.</p>
+
+<div class="figcenter" style="width: 390px;">
+<img src="images/fig_131.jpg" width="390" height="600" alt="Fig. 131." title="" />
+<span class="caption"><span class='smcap'>Fig. 131.</span>&mdash;Fichet-Heurtey purifier.</span>
+</div>
+<!--247.png--><p><span class='pagenum'><a name="Page_247" id="Page_247">[247]</a></span></p>
+
+<p><b>Gas-Holders.&mdash;</b>The purifiers by themselves constitute,
+to a certain extent, storage chambers for the gas
+before it is supplied to the engine; but in plants for the
+generation of gas without purifiers it is advisable to
+provide a gas-holder on the suction conduit near the
+engine.</p>
+
+<div class="figcenter" style="width: 355px;">
+<img src="images/fig_132.jpg" width="355" height="600" alt="Fig. 132." title="" />
+<span class="caption"><span class='smcap'>Fig. 132.</span>&mdash;Pintsch regulating-bell.</span>
+</div>
+
+<p>In order to save floor space the gas-holder may be
+placed in the basement. Preferably the capacity of
+the holder should be at least from 3 to 4 times the volume
+of the engine-cylinder. The holder should also
+be provided with a drain-cock and with a hand-hole
+located at some accessible point, so that the slimes and
+pitch which tend to accumulate in the holder can be
+removed. In some cases the gas-holder is formed by a
+<!--248.png--><span class='pagenum'><a name="Page_248" id="Page_248">[248]</a></span>
+small regulating bell, the function of which is to insure
+a uniform pressure. This bell is emptied during
+the suction period and is filled during the three succeeding
+periods of compression, explosion, and exhaust
+(Pintsch, Fig. 132).</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_133.jpg" width="600" height="228" alt="Fig. 133." title="" />
+<span class="caption"><span class='smcap'>Fig. 133.</span>&mdash;Types of gas-driers.</span>
+</div>
+
+<p><b>Drier.&mdash;</b>Sometimes, toward the end of a producer-gas
+pipe, a drier is located for the purpose of keeping
+back the water carried along, the drier being similar to
+that employed in steam conduits. It will, of course, be
+understood that such driers are useful only in plants
+having no purifiers (Fig. 133). The employment of
+the drier is advisable to prevent the entrance of moist
+gas into the cylinder and the condensation of moisture
+on the electric igniter.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_134.jpg" width="600" height="332" alt="Fig. 134." title="" />
+<span class="caption"><span class='smcap'>Fig. 134.</span>&mdash;Elbow with closure.</span>
+</div>
+
+<p><b>Pipes.&mdash;</b>The pipes connecting the several parts of
+<!--249.png--><span class='pagenum'><a name="Page_249" id="Page_249">[249]</a></span>
+a gas-producing plant should be disposed with particular
+care to insure tightness and cleanliness. It should
+be borne in mind that the gas is under a pressure below
+that of the atmosphere, and that the least leakage will
+cause the entrance of air, which will impair the quality
+of the gas. The greatest care should therefore be
+taken in fitting the joints. These joints are numerous,
+because there are joints wherever tubes are connected
+with each other and with the apparatus. Furthermore,
+all elbows should be provided with covers held
+in place by a yoke and compression screw, this being
+done for the purpose of providing for the introduction
+of a brush or other implement to remove the dust and
+pitch (Fig. 134).</p>
+
+<p>For conduits of small diameter the elbows with covers
+may be replaced with <b>T</b> connections, or connections
+provided with plugs.</p>
+
+<p>Gas piping in the immediate neighborhood of the
+cock for admitting gas to the motor should be provided
+with a conduit of proper diameter leading to the open
+air and serving to clean the apparatus and to fill them,
+during the operation of the fan, with gas suitable for
+combustion. This conduit should be provided with a
+stop-cock. Test-cocks for the gas should be placed on
+the piping immediately beyond the vaporizers, the
+scrubber, and near the engine.</p>
+
+<p>It will also be well to provide water-pressure gages
+before and after the scrubber to enable the attendant
+to ascertain the vacuum in the conduits and to adjust
+the running of the apparatus.
+<!--250.png--><span class='pagenum'><a name="Page_250" id="Page_250">[250]</a></span></p>
+
+<p><b>Purifying-Brush.&mdash;</b>As an additional precaution
+against the carrying of tar to the engine, metallic
+brushes are often employed, these brushes being spiral
+in form and enclosed in a cast-iron box interposed in
+the gas-supply pipe immediately after the engine. The
+gas will be broken up into streams by the obstacles
+formed by these brushes and will be freed of the suspended
+tar (Fig. 135). These brushes should be carefully
+cleaned at regular intervals. The best way of
+doing this is to drop them into kerosene or some other
+suitable solvent.</p>
+
+<div class="figcenter" style="width: 376px;">
+<img src="images/fig_135.jpg" width="376" height="600" alt="Fig. 135." title="" />
+<span class="caption"><span class='smcap'>Fig. 135.</span>&mdash;Metal purifying-brush.</span>
+</div>
+<!--251.png--><p><span class='pagenum'><a name="Page_251" id="Page_251">[251]</a></span></p>
+
+<h3>CONDITIONS OF PERFECT OPERATION
+OF GAS-PRODUCERS</h3>
+
+<p>These conditions depend upon the workmanship or
+upon the system of the plant, on the care with which
+it has been erected, on the nature of the fuel, on
+the condition of preservation of the apparatus, and
+upon the manner in which the producers have been
+working.</p>
+
+<p><b>Workmanship and System.&mdash;</b>The workmanship
+itself, which term is meant to include the choice of
+materials and the way they have been worked, presents
+no difficulty. The producers which we have discussed
+are very simple and offer absolutely no difficulties in
+their mechanical execution. As regards the system,
+however, especially with respect to the relative dimensions
+of the elements, it does not seem so far that it is
+possible to indicate any principle or rule capable of
+a rigid general application. It must be taken into
+account that the use of suction gas-generators has
+become general only in the last three or four years;
+the problem has therefore scarcely been adequately
+solved. However, some hints may be given on this
+subject.</p>
+
+<p><b>Generator.&mdash;</b>In regard to the generator, it is possible
+to deduce from the best existing plants the dimensions
+to be given to the generator relatively to those of
+the engine to be supplied, upon the assumption that the
+engine is single-acting and runs at a normal speed of
+<!--252.png--><span class='pagenum'><a name="Page_252" id="Page_252">[252]</a></span>
+from 160 to 230 revolutions per minute. The essential
+portion of the generator which contributes to the production
+of a proper gas is that which corresponds with
+the combustion zone. To this portion a cross-section is
+given varying in size between one-half and one-quarter
+of the surface of the engine-piston, sometimes between
+one-half and nine-tenths of this surface, according to
+the nature and the size of the fuel that is used. With
+small apparatus, however, ranging from 5 to 15 horse-power,
+the size of the base cannot be reduced below a
+certain limit, since otherwise the sinking of the fuel
+will be prevented. This danger always exists in small
+generators and renders their operation rather uncertain,
+such uncertainty being also due to the influence of the
+walls. It is to be noted that most modern generators are
+rather too large than otherwise.</p>
+
+<p>Many manufacturers of no wide experience have
+been led to make their apparatus rather large so as to
+insure a more plentiful production of gas. As a matter
+of fact, the fire in such apparatus is liable to be extinguished
+when the combustion is not very active. If the
+principles of the formation of gas in suction-generators
+be kept in mind, it is evident that the gas developed is
+the richer the "hotter" the operation of the apparatus.
+Such operation also permits the decomposition of the
+hydrogen and carbon monoxide.</p>
+
+<p>The "hot" operation of a generator is accomplished
+best with active combustion; and since this is a function
+of the rapidity with which the air is fed, it obviously is
+advantageous to reduce the area of the air-passage to a
+<!--253.png--><span class='pagenum'><a name="Page_253" id="Page_253">[253]</a></span>
+minimum as far as allowed by the amount of fuel to be
+treated. As to the height of the fuel in use in the apparatus,
+this varies as a rule between 4 and 5 times the
+diameter at the base.</p>
+
+<p><b>Vaporizer.&mdash;</b>The size of the vaporizer varies materially
+according to its type. No hard-and-fast rule
+can therefore be adopted for determining its heating
+surface; but this surface should in all cases be sufficient
+to vaporize under atmospheric pressure from .66 to .83
+pounds of water per pound of anthracite coal consumed
+in the generator.</p>
+
+<p><b>Scrubber.&mdash;</b>For the scrubbers, the following dimensions
+may be deduced from constructions now used by
+standard manufacturers.</p>
+
+<p>The volume of a scrubber is generally from six to
+eight times the anthracite capacity of the generator. A
+height of from three to four times the diameter is considered
+sufficient in most cases. It should be understood
+that in this height is included the water-pan
+chamber located below the partition or grate, and the
+upper chamber through which the gas escapes. The
+height of these two chambers depends necessarily upon
+the arrangement used for leading the gas to the lower
+portion of the washer and for the distribution of wash-water
+at the top.</p>
+
+<p><b>Assembling the Plant.&mdash;</b>The author has insisted
+strongly on the necessity of having all the apparatus
+and pipe connections perfectly tight. In order to ascertain
+if there is any leakage, the following procedure
+may be adopted:
+<!--254.png--><span class='pagenum'><a name="Page_254" id="Page_254">[254]</a></span></p>
+
+<p>When starting the fire by means of wood, straw, or
+other fuel producing smoke, instead of allowing this
+smoke to escape through the flue during the operation
+of the fan, it may be caused to escape through the cock
+which generally admits the gas to the motor, the cock
+being opened for this purpose. The damper in the outlet
+flue is closed. In this manner the smoke will fill all
+the apparatus and connecting pipes under a certain
+pressure and will escape through any cracks, the presence
+of which will thus be revealed.</p>
+
+<p>Another test, which is made during the ordinary operation
+of the generator, consists in passing a lighted
+candle along the joints; if there is any leakage, this will
+be shown by a deviation of the flame from a vertical
+position.</p>
+
+<p><b>Fuel.&mdash;</b>We have discussed the subject of fuel in a
+preceding chapter (Chapter XIII) and have indicated
+the conditions to be fulfilled by low grade or anthracite
+coal best adapted for use in suction gas-generators. It
+may here be added that the coal used in the generator
+should be as dry as possible and in pieces of from
+<sup>1</sup>&frasl;<sub>2</sub> inch to 1 inch. Very small pieces, and particularly
+coal dust, are injurious and should be removed by preliminary
+screening as far as possible. Screened coal
+is thrown in with an ordinary grate shovel.</p>
+
+<p><b>How to Keep the Plant in Good Condition.&mdash;</b>In
+regard to the generator, apart from the cleaning of the
+grate and of the ash-pit, which may be done during
+operation, it is necessary to empty the apparatus entirely
+once a week, if possible, in order to break off the
+<!--255.png--><span class='pagenum'><a name="Page_255" id="Page_255">[255]</a></span>
+clinkers adhering to the retort. These clinkers destroy
+the refractory lining, form rough projections interfering
+with the downward movement of the fuel, bring
+about the formation of arches, and reduce the effective
+area of the retort. At the time of this cleaning, tests
+are also made as to the tightness of the doors of the
+combustion-chamber, of the charging-boxes, etc.</p>
+
+<p>The vaporizer should be cleaned every week or every
+other week, according to the more or less bituminous
+character of the fuel and the greater or smaller content
+of lime in the water used. Lime deposits may be
+eliminated, or the salts may be precipitated in the form
+of non-adhering slimes, by introducing regularly a
+small amount of caustic potash or soda into the feed-water.
+If the deposits or incrustations are very tenacious,
+the use of a dilute solution of hydrochloric acid
+may be resorted to. Tar which may adhere to the
+conduits, pipes or gas passages, is best removed while
+the apparatus is still hot, or a solvent may be employed,
+such as kerosene, turpentine, etc. The connections between
+the vaporizer and the scrubber are particularly
+liable to become obstructed by the accumulation of tar
+or dust carried along by the gas.</p>
+
+<p>It is advisable to examine the several parts of the
+plant once or twice a week by opening the covers or the
+cleaning-plugs.</p>
+
+<p>The lower compartment of the washer keeps back
+the greater part of the dust which has not been retained
+in collectors or boxes provided especially for this purpose.
+The dust takes the form of slime, and, in some
+<!--256.png--><span class='pagenum'><a name="Page_256" id="Page_256">[256]</a></span>
+arrangements of apparatus, tends to clog up the overflow
+pipe, thus arresting the passage of gas and causing
+the engine to stop. This portion of the washer should
+be thoroughly cleaned once or twice a month.</p>
+
+<p>If very hard blast-furnace coke is used in the washer,
+it may be kept in use for over a year without requiring
+removal. In order to free the purifying materials from
+dust and lime sediments carried along by the wash-water,
+it is well to let the wash-water flow as abundantly
+as possible for about a half-hour at least once a month.
+At the time of renewing the purifying material the
+precautions indicated in the section dealing with these
+matters should be observed, and care should be taken
+to have shelves or gratings on which the material is
+supported in layers not too thick, so as to avoid any
+resistance to the passage of the gas.</p>
+
+<p>In a general way it is advisable to test the drain-cocks
+on the several apparatus daily, and to keep them
+in perfect condition. If, when open, one of these cocks
+does not discharge any gas, water, or steam, a wire
+should be introduced into the bore to make sure it is
+not clogged up.</p>
+
+<p><b>Care of the Apparatus.&mdash;</b>Each producer-gas plant
+will require special instructions for running it, according
+to the system, the construction, and the size of the
+plant. Such instructions are generally furnished by
+the manufacturer. However, there are some general
+rules which are common to the majority of suction gas-producers,
+and these will here be enumerated.</p>
+
+<p><b>Starting the Fire for the Gas Generator.&mdash;</b>This
+<!--257.png--><span class='pagenum'>257</span>
+operation calls for the presence of the engineer of the
+plant and an assistant. The proper procedure is as follows:</p>
+
+<p>First: Open the doors of the furnace and of the ash-pit.
+Then open the outlet flue and make sure that the
+grate of the generator is clear of ashes and clinkers. It
+should also be seen to that the parts of the charging-box
+work well and that the joints are tight.</p>
+
+<p>Second: Ascertain whether there is the proper
+amount of water in the vaporizer, in the scrubber, etc.,
+and that the feed works properly.</p>
+
+<p>Third: Through the door of the combustion-chamber
+introduce straw, wood shavings, cotton waste, etc.;
+light them and fill the generator with dry wood up to
+one-quarter or one-half of its height; then add a few
+pailfuls of coal.</p>
+
+<p>Fourth: Close the doors of the ash-pit and of the
+combustion-chamber and start the draft by means of the
+fan. As soon as the draft is started, it must be kept up
+without interruption until the engine begins to run,
+which may be ten or twenty minutes after lighting
+the fire.</p>
+
+<p>Fifth: After the draft has been continued for a few
+minutes, the coal becomes sufficiently incandescent to
+start the production of gas, which may be ascertained
+by trying to light the gas at the test-cock near the generator.
+Then the opening in the outlet flue is half
+closed for the purpose of producing pressure in the
+apparatus.</p>
+
+<p>Sixth: Open the outlet flue adjacent to the engine for
+<!--258.png--><span class='pagenum'><a name="Page_258" id="Page_258">[258]</a></span>
+the purpose of purging the apparatus and the conduits
+of the air which they contain until the gas may be
+lighted at the test-cock placed near the motor.</p>
+
+<p>Seventh: Adjust the normal outflow of wash-water
+for the scrubber.</p>
+
+<p>Eighth: As soon as the gas burns continuously at the
+test-cock with an orange-colored flame the engine may
+be started.</p>
+
+<p>The gas at first burns with a blue flame; this color
+indicates that it contains a certain amount of air. The
+opening of the test-cock should be so regulated as to
+reduce the outlet pressure of the gas sufficiently to prevent
+the flame from going out. During the production
+of the draft, as well as during the ordinary running of
+the plant, the filling of the apparatus with fuel should
+be done with care to prevent explosions of gas due to the
+entrance of air. Particular care should be taken never
+to open at the same time the lid of the charging-box and
+the device, be it a cock, valve, or damper, which controls
+the connection of the charging-box with the generator.
+All the operations which have been mentioned
+above should be carried out as quickly as possible.</p>
+
+<h3>STARTING THE ENGINE</h3>
+
+<p>The manner of starting the engine depends on the
+type of the engine and on the starting device with
+which it is provided, as we have already explained in
+connection with engines working with gas from city
+mains.
+<!--259.png--><span class='pagenum'><a name="Page_259" id="Page_259">[259]</a></span></p>
+
+<p>It is, however, important for the production of a
+good explosive mixture to regulate the amount of air
+supplied to the engine according to the quality of the
+gas employed. It is advisable to continue the operation
+of the fan until several explosions have taken place in
+the cylinder and the engine has acquired a certain
+speed so as to be able to draw in the normal amount
+of gas.</p>
+
+<p>Naturally the gas-outlet tube near the admission-cock
+should be closed after starting the engine, as
+well as the opening in the outlet flue of the generator.
+When the motor is running properly, the amount of
+water fed to the vaporizer and overflowing to the ash-pit
+is properly adjusted. The generator is then filled
+up to the level indicated by the manufacturer.</p>
+
+<p><b>Care of the Generator during Operation.&mdash;</b>As
+soon as the apparatus is running under normal conditions,
+it presents the advantage of requiring only very
+slight supervision and very little manual tending. The
+supervision consists:</p>
+
+<p>First: In regulating and keeping up a proper feed
+of water to the vaporizer.</p>
+
+<p>Second: In seeing to it that in apparatus provided
+with an overflow leading to the ash-pit, the water
+should flow constantly but without exceeding the
+proper amount.</p>
+
+<p>Third: In keeping down temperature in the scrubber
+by properly regulating the feed of the wash-water.
+This apparatus may be slightly warm at its lower part,
+but must be quite cold at the top.
+<!--260.png--><span class='pagenum'>260</span></p>
+
+<p>The manual tending to be done is limited to the regular
+filling up of the generator with fuel and to the
+removal of ashes and clinkers. The charging is effected
+at regular intervals, which, according to the various
+types of anthracite-generators, vary from one to six
+hours. Charging the apparatus at short intervals entails
+unnecessary labor, while charging at too long
+intervals will often interfere with the uniform production
+of the gas.</p>
+
+<p>It will be obvious that the amount of fuel introduced
+will be the larger, the greater the intervals between two
+fillings. This fuel is cold and contains between its
+particles a certain amount of air; furthermore, the layer
+of coal which covers the incandescent zone has become
+relatively thin. The excess of air impoverishes the gas,
+and the fresh fuel lowers the temperature of the mass
+undergoing combustion, so that again the gas in process
+of formation is weakened. Experience seems to show
+that as a rule it is best to fill up the generator at intervals
+of from two to three hours, according to the work
+done by the engine. It should be noted that the level
+of the fuel in the generator should not sink below the
+bottom of the feed-hopper.</p>
+
+<p>The author wishes again to emphasize that in order
+to prevent the harmful entrance of air, the charging
+operations should be carried out as quickly as possible;
+and for this reason the fuel should be introduced not by
+means of the shovel, but by means of a pail, scuttle, or
+other appropriate receptacle.</p>
+
+<p>Care should be taken to fill the charging box to its
+<!--261.png--><span class='pagenum'><a name="Page_261" id="Page_261">[261]</a></span>
+upper edge and to adjust its cover accurately before
+operating the device which closes the feed-hopper
+(valve, cock).</p>
+
+<p>The removal of the ashes and clinkers should be accomplished
+as infrequently as possible, since opening
+the doors of the ash-pit and of the combustion-chamber
+necessarily causes an inward suction of cold air which
+is harmful.</p>
+
+<p>As a rule with generators employing anthracite coal,
+it is sufficient to empty the ash-pit twice daily; this
+should be preferably done during stoppages. However,
+the cleaning of the grate by means of a poker
+passed between the grate-bars or over them in order
+to bring about the falling of the ashes, should be attended
+to every two to four hours, according to the type
+of the generator and the nature of the fuel. In order
+that this cleaning may be done without opening the
+doors, the latter should be provided with apertures having
+closing devices.</p>
+
+<p>This cleaning has for its chief object to allow the free
+passage of the air for supporting combustion and to
+keep the incandescent zone in the apparatus at the
+proper height. The accumulation of ashes and clinkers
+at the bottom of the retort will shift this zone upward
+and impair the quality of gas.</p>
+
+<p><b>Stoppages and Cleaning.&mdash;</b>After closing the gas-inlet
+to the engine, the damper in the gas-outlet flue
+of the generator should be opened and the cocks controlling
+the feed of water to the scrubber and to the
+vaporizer should be closed.
+<!--262.png--><span class='pagenum'>262</span></p>
+
+<p>If it is desired to keep up the fire of the generator
+during the stoppage so as to be able to start again
+quickly, the ash-pit door should be opened so as to produce
+a natural draft which will maintain combustion.
+While the door is open, the clinkers which have
+accumulated above the grate may be removed, as they
+are much more easily taken off the grate when they
+are hot.</p>
+
+<p>At least once a week the fire in the generator should
+be put out and the generator completely cleaned&mdash;that
+is, when ordinary fuel is employed. For this purpose,
+as soon as the apparatus is stopped, a portion of the incandescent
+fuel is withdrawn through the doors of the
+combustion-chamber, and the retort is allowed to cool
+before it is emptied entirely. Too sudden a cooling of
+the retort may injure its refractory lining. In order
+to prevent explosions caused by the entrance of air, the
+feed-hopper should remain hermetically closed during
+the removal of the incandescent fuel through the doors
+of the combustion-chamber.</p>
+
+<p>If the apparatus is placed in a room poorly ventilated,
+the cleaning should be attended to by two men,
+so that one may assist the other in case he is overcome
+by the gas. In all cases there should be a strict prohibition
+against the use of any light having an exposed
+flame liable to set on fire the explosive mixtures which
+may be formed.</p>
+
+<p>When the generator, after cooling, is completely
+open, the charging-box is taken apart, and, if necessary,
+the feed-hopper also; the grates are taken out, if necessary;
+<!--263.png--><span class='pagenum'>263</span>
+and, by means of a poker inserted from above, the
+clinkers and slag adhering to the retort are broken
+off.</p>
+
+<p>In the foregoing paragraphs the author has indicated
+how the several apparatus, such as the vaporizer, the
+washer, the conduits, etc., should be attended to and
+maintained in good working order.</p>
+
+<hr class="ChapterTopRule" />
+<!--264.png--><p><span class='pagenum'><a name="Page_264" id="Page_264">[264]</a></span></p>
+<h2><a name="CHAPTER_XIV" id="CHAPTER_XIV"></a>CHAPTER XIV</h2>
+
+<div class="c3">OIL AND VOLATILE HYDROCARBON ENGINES</div>
+
+<p>Although this book is devoted primarily to a discussion
+of street-gas and producer-gas engines employed
+in various industries, a few words on oil and
+volatile hydrocarbon engines may not be out of place.</p>
+
+<p>Oil-engines are those which use ordinary petroleum
+as a fuel or illuminating oil of yellowish color, having
+a specific gravity varying from 0.800 to 0.820 at a temperature
+of 15 degrees C. (59 degrees F.), and boiling
+between 140 and 145 degrees C. (284 to 297 degrees
+F.). Volatile hydrocarbon engines are those which
+employ light oils obtained by distilling petroleum.
+These oils are colorless, have a specific gravity that
+varies from 0.680 to 0.720, and boil between 80 degrees
+and 115 degrees C. (176 to 257 degrees F.). Among
+these "essences," as they are called in Europe, may be
+mentioned benzine and alcohol.</p>
+
+<p>In general appearance, and the way in which they
+are controlled, oil-engines differ but little from gas-engines.
+Their usual speed, however, is 20 to 30 per
+cent. greater than that of gas-engines. Except in some
+engines of the Diesel and Banki types, the compression
+does not exceed 43 to 71 pounds per square inch. In
+volatile hydrocarbon engines, on the other hand, the
+speed is very high, often running from 500 to 2,000
+<!--265.png--><span class='pagenum'><a name="Page_265" id="Page_265">[265]</a></span>
+revolutions per minute, while the speed of gas or oil
+engines rarely exceeds 250 or 300 revolutions per
+minute.</p>
+
+<p><b>Oil-Engines.&mdash;</b>Oil-engines are employed chiefly in
+Russia and in America. Because of the high price of
+oil in other countries they are to be found only in small
+installations in country regions and are used mainly
+for driving locomobiles and launches. The improvements
+which have been made of late years in the construction
+of gas-engines supplied by suction gas-producers
+for small as well as for large powers, have hindered
+the general introduction of oil-engines.</p>
+
+<p>The characteristic feature in the design of many of
+the oil-engines of the four-cycle type now in use (to
+which type we shall confine this discussion) is to be
+found in the controlling mechanism employed. The
+underlying principle of this mechanism lies not in acting
+upon the admission-valve, but in causing the governor
+to operate the exhaust-valve in such a manner that it
+is held open whenever the engine tends to exceed its
+normal speed. Some engines, however, are built on the
+principle of the gas-engine, with an admission-valve so
+controlled by the governor that it is open during normal
+operation and closed whenever the speed becomes
+excessive.</p>
+
+<p>The necessity of producing a mixture of air and oil
+capable of being ignited in the engine-cylinder has
+led to the invention of various contrivances, which
+cannot be used if illuminating-gas or producer-gas be
+employed. These contrivances are the atomizer, the
+<!--266.png--><span class='pagenum'><a name="Page_266" id="Page_266">[266]</a></span>
+carbureter, the oil-pump, the air-pump, the oil-tank,
+and the oil-lamp. In some oil-engines all of the elements
+may be found, but for the purpose of simplifying
+the construction and of avoiding unnecessary complications,
+manufacturers devised arrangements which rendered
+it possible to discard some of them, particularly
+those of delicate construction and operation. It is
+not the intention of the author to enter into a detailed
+description of these various devices, since the limitations
+of this book would be considerably surpassed. The
+reader is referred to books on the oil-engine, published
+in the United States, England, and France.<a name="FNanchor_B_2" id="FNanchor_B_2"></a>
+<a href="#Footnote_B_2" class="fnanchor">[B]</a></p>
+
+<p>Most of the observations which have been made on
+the construction and installation of gas-engines, as well
+as the precautions which have been advised in the conduct
+of an engine, apply with equal force to oil-engines.
+It will therefore be unnecessary to recur to this phase
+of the subject so far as oil-engines are concerned. One
+point only should be insisted upon&mdash;the necessity of
+very frequently cleaning the valves and moving parts
+of the engine.</p>
+
+<p>Illuminating-oil when burnt produces sooty deposits,
+particularly if combustion be incomplete, which deposits
+foul the various parts and cause premature ignitions
+and faulty operation.</p>
+
+<!--267.png--><p><span class='pagenum'><a name="Page_267" id="Page_267">[267]</a></span></p>
+
+<p>The use of oil in atomizers, carbureters, and lamps
+is accompanied with the employment of pipes and openings
+so small in cross-section that the slightest negligence
+is attended with the formation of partial obstructions
+that inevitably affect the operation of the engine.</p>
+
+<p><b>Volatile Hydrocarbon Engines.&mdash;</b>Only those engines
+will here be treated which have become of importance
+in the development of the automobile.</p>
+
+<p>Some designers have attempted to employ the volatile
+hydrocarbon engine for industrial and agricultural
+purposes, and have devised electro-generator groups,
+hydraulic groups, and so-called "industrial combinations"
+in which belt and pulley transmission is employed.
+These applications in particular will here be
+rapidly reviewed.</p>
+
+<p>The high speed at which engines of this class are
+driven renders it possible to operate a centrifugal pump
+directly and to mount both the engine and machine
+which it actuates on the same base. The hydrocarbon
+engine has the merit of being very light and of taking
+up but little room. Its cost is considerably less than
+that of an oil or producer-gas engine of corresponding
+power. On the other hand, its maintenance is much
+more expensive, and the hydrocarbons upon which it
+depends for fuel anything but cheap. Furthermore,
+the engines wear away rapidly, on account of their high
+speed. For this reason it is advisable to base calculations
+on a life of three to four years, while oil and gas
+engines may generally be considered to be still of service
+at the end of thirteen years. On the following
+<!--268.png--><span class='pagenum'><a name="Page_268" id="Page_268">[268]</a></span>
+page a comparison of costs for installation and maintenance
+is drawn between the oil and hydrocarbon
+engine on the basis of ten horse-power.</p>
+
+<p><b>Comparative Costs.&mdash;</b>A 10 horse-power oil-engine,
+in the matter of first cost of installation, is about 35
+per cent. more expensive than a volatile hydrocarbon
+engine of equal power. On the other hand, the operating
+expenses of the oil-engine are less by 25 per cent.
+than they are for the volatile hydrocarbon engine.</p>
+
+<p>The engines which are here discussed usually have
+their cylinders vertically arranged, as in steam-engines
+of the overhead cylinder type. The crank-shaft and
+the connecting-rods are enclosed in a hermetically
+sealed box filled with oil, so that the movement of the
+parts themselves ensures the liberal lubrication of the
+piston. The suction-valve is generally free, although
+latterly designers have shown a tendency to connect
+it with the cam-shaft, with the result that it has become
+possible to reduce the speed appreciably without stopping
+the engine. The carbureter is operated by the
+suction of the engine. If the fuel employed is alcohol,
+it must be heated.</p>
+
+<p><b>Tests of High-speed Engines.&mdash;</b>High-speed engines
+present various difficulties which must be contended
+with in controlling their operation. Their high speed
+renders it impossible to take indicator records as in the
+case of most industrial engines. Indicator cards, moreover,
+at best give but very crude data, which relate to
+each explosion cycle only, and which are therefore inadequate
+in determining the exact conditions of an engine's
+<!--269.png--><span class='pagenum'><a name="Page_269" id="Page_269">[269]</a></span>
+operation. Oil, benzine, and other so-called carbureted-air
+engines are particularly difficult to control
+because of many phenomena which cannot be recorded.
+In order to test the operation of high-speed engines,
+two different types of instruments are at present employed:
+the manograph and the continuous explosion recorder.</p>
+
+<p><b>The Manograph.&mdash;</b>The manograph, which is the
+invention of Hospitalier, is an optical instrument in
+which a series of closed diagrams are superimposed
+upon a polished mirror similar in form to Watt
+diagrams. Because the images persist in affecting the
+retina of the eye an absolutely continuous, but temporary,
+gleam is seen. Still, it is possible to obtain a
+photograph or a tracing of these diagrams.</p>
+
+<p><b>The Continuous Explosion Recorder for High-speed
+Engines.&mdash;</b>The author has devised an explosion
+and pressure recorder, which is mounted upon the
+explosion chamber to be tested and which communicates
+with the chamber through the medium of a
+cock <i>r</i> (Fig. 136). The instrument is somewhat similar
+in form to the ordinary indicator. Its record, however,
+is made on a paper tape which is continuously unwound.
+The cylinder <i>c</i> is provided with a piston <i>p</i>,
+about the stem of which a spring <i>s</i> is coiled. A clock
+train contained in the chamber <i>b</i> unwinds the strip of
+paper from the roll <i>p&#8242;</i> and draws it over the drum <i>p&#8242;&#8242;</i>,
+where the pencil <i>t</i> leaves its mark. The tape is then
+rewound on the spindle <i>p&#8242;&#8242;&#8242;</i>. A small stylus or pencil <i>f</i>
+traces "the atmospheric line" on the paper as it passes
+<!--270.png--><span class='pagenum'>270</span>
+over the drum <i>p&#8242;&#8242;</i>. In order to obviate the binding of
+the piston <i>p</i> when subjected to the high temperature of
+the explosions, the cylinder <i>c</i> is provided with a casing
+<i>e</i> in which water is circulated by means of a small rubber
+tube which fits over the nipple <i>e&#8242;</i>. This recorder
+<!--271.png--><span class='pagenum'>271</span>
+analyzes with absolute precision the work of all engines,
+whatever may be their speed. It gives a continuous
+graphic record from which the number of explosions,
+together with the initial pressure of each, can
+be determined, and the order of their succession. Consequently
+the regularity or irregularity of the variations
+can be observed and traced to the secondary influences
+producing them, such as the section of the inlet and outlet
+valves and the sensitiveness of the governor. It
+renders it possible to estimate the resistance to suction
+and the back pressure due to expelling the burnt gases,
+the chief causes of loss in efficiency in high-speed engines.
+Furthermore, the influence of compression is
+markedly shown from the diagram obtained.</p>
+
+<div class="figcenter" style="width: 370px;">
+<img src="images/fig_136.jpg" width="370" height="600" alt="Fig. 136." title="" />
+<span class="caption"><span class='smcap'>Fig. 136.</span>&mdash;R. Mathot&#39;s continuous explosion
+recorder.</span>
+</div>
+
+<!--272.png--><p><span class='pagenum'>272</span></p>
+<div class="figcenter" style="width: 700px;">
+<img src="images/fig_137.jpg" width="700" height="163" alt="Fig. 137." title="" />
+<span class="caption"><span class='smcap'>Fig. 137.</span>&mdash;12 H.P. Oil-engine.</span>
+</div>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_138.jpg" width="600" height="203" alt="Fig. 138." title="" />
+<span class="caption"><span class='smcap'>Fig. 138.</span>&mdash;6 H.P. Volatile Hydrocarbon Engine.</span>
+</div>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_139.jpg" width="600" height="229" alt="Fig. 139." title="" />
+<span class="caption"><span class='smcap'>Fig. 139.</span>&mdash;Effect of size of section and exhaust
+ports.</span>
+</div>
+
+<p>The recorder is mounted on the engine; its piston is
+driven back by each of the explosions to a height corresponding
+with their force; and the stylus or pencil
+controlled by the lever <i>t</i> records them side by side on
+the moving strip of paper. The speed with which this
+strip is unwound conforms with the number of revolutions
+of the engine to be tested, so that the records
+of the explosions are placed side by side clearly and
+legibly. Their succession indicates not only the number
+of explosions and of revolutions which occur in
+a given time, but also their regularity, the number
+of misfires. The atmospheric pressure of the explosions
+is measured by a scale connected with the recorder-spring.
+By employing a very weak spring
+which flexes at the bottom simply by the effect of
+the compression in the engine-cylinder, it is possible
+<!--273.png--><span class='pagenum'><a name="Page_273" id="Page_273">[273]</a></span>
+to ascertain the amount of the resistance to suction and
+to the exhaust. It is simply sufficient to compare the
+explosion record with the atmospheric line, traced by
+the stylus <i>f</i>. By means of this apparatus, and of the
+records which it furnishes, it is possible analytically to
+regulate the work of an engine, to ascertain the proportion
+of air, gas, or hydrocarbon, which produces the
+most powerful explosion, to regulate the compression,
+the speed, the time of ignition, the temperature, and the
+like (Figs. 137, 138 and 139).</p>
+
+<p>In order to explain the manner of using this recorder
+several specimen diagrams are here given.</p>
+
+<p>I. <i>Determination of the Amount of Compression.</i>&mdash;A
+spring of average power is employed, the total flexion
+of which corresponds almost with the maximum compression
+so as to obtain a curve of considerable amplitude.
+The engine is first revolved without producing
+explosions, driving it from the dynamo usually employed
+in shops, at the different speeds to be studied.
+The compression of the mixture varies in inverse ratio
+to the number of revolutions of the shaft, owing to the
+resistances which are set up in the pipes and the valves
+and which increase with the speed. The accompanying
+cut (Fig. 140) shows two distinct records taken in
+two different cases, namely:</p>
+
+<p>A.&mdash;Speed of engine, 950 revolutions per minute;
+amount of compression, 68.9 pounds per square inch.</p>
+
+<p>B.&mdash;Speed of engine, 1,500 revolutions per minute;
+amount of compression, 61 pounds per square inch, or
+11.5 per cent. less.
+<!--274.png--><span class='pagenum'><a name="Page_274" id="Page_274">[274]</a></span></p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_140.jpg" width="600" height="213" alt="Fig. 140." title="" />
+<span class="caption"><span class='smcap'>Fig. 140.</span></span>
+</div>
+
+<p>II. <i>Determination of the Resistance to Suction and
+Exhaust.</i>&mdash;Influence of the tension of the spring of the
+suction valve and of the section of the pipe. Effect of
+the section of the exhaust-valve and of the length and
+shape of the exhaust-pipe:</p>
+
+<p>A very light spring is utilized, the travel of which is
+limited by a stop so as to obtain on a comparatively
+large scale the depressions and resistance respectively
+represented by the position of the corresponding curve,
+above or below the atmospheric line (Fig. 141).</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_141.jpg" width="600" height="101" alt="Fig. 141." title="" />
+<span class="caption"><span class='smcap'>Fig. 141.</span></span>
+</div>
+
+<p>C.&mdash;Tension of the suction-valve: 2.9 pounds. Resistance
+to suction: <sup>1</sup>&frasl;<sub>7</sub> of an atmosphere (2.7 pounds).</p>
+
+<p>D.&mdash;Tension of the suction-valve: 2.17 pounds. Resistance
+to suction: <sup>2</sup>&frasl;<sub>7</sub> of an atmosphere (5.4 pounds).</p>
+
+<p>E.&mdash;A chest is used for the exhaust. Resistance to
+exhaust: <sup>2</sup>&frasl;<sub>7</sub> of an atmosphere (5.4 pounds).</p>
+
+<p>F.&mdash;The exhausted gases are discharged into the air,
+<!--275.png--><span class='pagenum'><a name="Page_275" id="Page_275">[275]</a></span>
+the pipe and the chest being discarded. Resistance to
+the exhaust is zero (Fig. 142).</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_142.jpg" width="600" height="144" alt="Fig. 142." title="" />
+<span class="caption"><span class='smcap'>Fig. 142.</span></span>
+</div>
+
+<p>The depression graphically recorded is partly due
+to the inertia of the spring of the explosion-recorder,
+which spring expands suddenly when the exhaust is opened.</p>
+
+<p>III. <i>Comparison of the Average Force of the Explosions
+by Means of Ordinates.</i>&mdash;A powerful spring is
+employed. The paper band or tape of the recorder
+is moved with a small velocity of translation so as to
+approximate as closely as possible the corresponding
+ordinates representing the explosions (Fig. 143).</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_143.jpg" width="600" height="222" alt="Fig. 143." title="" />
+<span class="caption"><span class='smcap'>Fig. 143.</span></span>
+</div>
+
+<p>G.&mdash;Pure alcohol. Explosive force, 369.72 to 426.6
+pounds per square inch.</p>
+
+<p>H.&mdash;Carbureted alcohol. Explosive force, 397.6 to
+510.8 pounds per square inch.</p>
+
+<p>I.&mdash;Volatile hydrocarbon. Explosive force, 483.48
+to 531.92 pounds per square inch.
+<!--276.png--><span class='pagenum'><a name="Page_276" id="Page_276">[276]</a></span></p>
+
+<p>IV. <i>Analysis of a Cycle by Means of Open Diagrams
+Representing the Four Periods.</i>&mdash;A powerful spring is
+employed, and the paper is moved with its maximum
+speed of translation. The four phases of the cycle are
+easily distinguished as they succeed one another graphically
+from right to left in other words, in a direction
+opposite to that in which the paper is unwound. A
+diagram is made which reproduces exactly the values
+of the corresponding pressures at different points in the
+travel of the piston (Fig. 144). The periods of the
+cycle are reproduced as faithfully as if the ordinary indicator
+which gives a closed curved diagram had been
+employed. There is no difficulty in reading the record,
+since the paper is not in any way connected with the
+engine-piston. Some attempts have been made to secure
+open diagrams in which the motion of translation given
+to the paper is controlled by the engine itself; but these
+apparatus as well as the ordinary indicators cannot be
+used when the speed of the engine exceeds 400 to 500
+revolutions per minute.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_144.jpg" width="600" height="132" alt="Fig. 144." title="" />
+<span class="caption"><span class='smcap'>Fig. 144.</span></span>
+</div>
+
+<p>J.&mdash;Speed, 1,200 revolutions; carbureted alcohol;
+average force of the explosions, 426.6 pounds per
+square inch. Average compression, 92.43 pounds per
+square inch. Pressure at the end of the expansion,
+21.33 pounds per square inch.
+<!--277.png--><span class='pagenum'><a name="Page_277" id="Page_277">[277]</a></span></p>
+
+<p>V. <i>Analysis of the Inertia of the Recorder. Selection
+of the Spring to be Employed.</i>&mdash;Given the rapidity
+with which the explosions succeed one another in automobile
+engines, it is readily understood that the inertia
+of the moving parts of the recorder will be graphically
+reproduced (Fig. 144). The effect of this inertia is a
+function of the weight of the moving parts and of the
+extent of their travel.</p>
+
+<p>The moving masses are represented by the piston and
+its rod, the spring and the levers of the parallelogram
+stylus. The effects due to inertia have been considerably
+lessened by reducing the weight of the various
+parts to a minimum. A hollowed piston, a hollowed
+rod and short and light levers have been adopted. The
+traditional pencil has been displaced by a silver point
+which traces its mark upon a metallically coated paper.
+For the heavy springs with their long travel, light but
+powerful springs with small amplitudes have been substituted.
+Since the perfect lubrication of the recorder-cylinder
+is of great importance, a simple oiling device
+certain in its action has been adopted. The recess of the
+piston forms a cup that can be filled with oil whenever
+the spring is changed.</p>
+
+<p>At each explosion the violent return of the piston
+splashes oil against the cylinder walls and thus insures
+perfect lubrication. It should be observed that if the
+directions given are not followed, particularly in the
+choice of a spring suitable for each experiment, inertia
+effects will be produced. These can easily be detected
+on the record and cannot be confused with the curves
+<!--278.png--><span class='pagenum'>278</span>
+which interpret the phenomena occurring in the cylinder
+of the engine. At a height equal to the end
+of the piston's stroke, the cylinder of the recorder is
+provided with a water-jacket which keeps the temperature
+down to a proper point and prevents the binding of
+the piston.</p>
+
+<p>The explosion-chamber of automobile engines being
+rather small in volume, should not be sensibly increased
+in order that the record obtained may conform as nearly
+as possible with actual working conditions on the road.
+In order to attain this end the cylinder of the recorder
+is so disposed that the piston travels to the height of the
+connecting-cock. As a result of this arrangement the
+field of action of the gases is reduced to a minimum.
+Since these gases have no winding path to follow, they
+are subjected neither to loss of quantity nor to cold.</p>
+
+<h3>FOOTNOTES:</h3>
+
+<div class="footnote"><p><a name="Footnote_B_2" id="Footnote_B_2"></a>
+<a href="#FNanchor_B_2"><span class="label">[B]</span></a> Hiscox, Gas and
+Oil Engines, Norman W. Henley Pub. Co., New
+York. Parsell and Weed, Gas and Oil Engines, 1900, Norman W.
+Henley Pub. Co., New York. Goldingham, 1900, Spon &amp; Chamberlain,
+London. Dugald Clerk, 1897, Longmans, London. Grover, 1902, Heywood,
+Manchester. Aim&eacute;. Witz, 1904, Barnard, Paris. H. G&uuml;ldner, 1903,
+Springer, Berlin.</p></div>
+
+<hr class="ChapterTopRule" />
+<!--279.png--><p><span class='pagenum'><a name="Page_279" id="Page_279">[279]</a></span></p>
+<h2><a name="CHAPTER_XV" id="CHAPTER_XV"></a>CHAPTER XV</h2>
+
+<div class="c3">THE SELECTION OF AN ENGINE</div>
+
+<p>The conditions which must be fulfilled both by engines
+and gas-producers in order that they may industrially
+operate with regularity and economy have
+been dwelt upon at some length. Unfortunately it often
+happens that engines are not installed as they should be,
+with the result that they run badly and that the reputation
+of gas-engines suffers unjustly. The use of suction
+gas-producers in particular caused considerable trouble
+at first owing to inexperience, so that even now many
+hesitate to adopt them despite their great economical
+advantages. The reason assigned for this hesitation is
+the supposed danger attending their operation.</p>
+
+<p>The factory proprietor who intends to install a gas-engine
+in his plant is not usually able to appreciate the
+intrinsic value of one engine when compared with another,
+or to determine whether the plans for an installation
+conform with the best practice. The innumerable
+types of engines offered to him by manufacturers and
+their agents, each of whom claims to have a better engine
+than his rivals, plunges the purchaser into hesitation
+and doubt. Not knowing which engine to select, he
+usually buys the cheapest. Very often he learns, as time
+goes by, that his installation is far from being perfect.
+<!--280.png--><span class='pagenum'>280</span>
+Finally he begins to believe that he ought to consult an
+expert. The author's personal experience has convinced
+him that eight times out of ten the factory owner
+who has picked out an engine for himself has not obtained
+an installation which meets the requirements
+which the manufacturers of gas-engines should fulfil.
+Many of these requirements could be complied with
+were it not for the fact that the manufacturer has
+dropped certain details which appeared superfluous,
+but which were in reality very important in obtaining
+perfect operation. The author therefore suggests that
+the services of a competent expert be retained by those
+who intend to install a gas-engine in their plants.</p>
+
+<p><b>The Duty of a Consulting Engineer.&mdash;</b>An expert
+fills the same office as an architect, and impartially
+selects the engine best suited to his client's peculiar
+needs. His examination of the engines offered to him
+will proceed somewhat according to the following programme:</p>
+
+<p>1. He will first study the installation from the
+mechanical point of view, and also the local conditions
+under which that installation is to operate, in order that
+he may not order an engine too large or too small, or
+a type incompatible with the foundations at his disposal,
+or unable to fulfil all the requirements of his
+client.</p>
+
+<p>2. He will examine the precautions which have been
+taken to avoid or reduce to a minimum certain inconveniences
+which attend the operation of explosion-engines.
+<!--281.png--><span class='pagenum'><a name="Page_281" id="Page_281">[281]</a></span></p>
+
+<p>3. He will draw up specifications, with the terms
+of which gas-engine makers must comply, so that he can
+compare on the basis of these specifications the merits
+of the engines submitted to him.</p>
+
+<p>4. He will prepare an estimate of cost and also a
+contract which is not couched in terms altogether in the
+gas-engine maker's favor, and which gives the purchaser
+important warranties.</p>
+
+<p>5. He will supervise the technical installation of the
+engine or plant.</p>
+
+<p>6. He will make tests after the engine is installed and
+see to it that the maker has fulfilled his warranties.</p>
+
+<p><b>Specifications.&mdash;</b>Since engines and gas-producers are
+constructed for commercial ends, it naturally follows
+that their manufacturers seek to make the utmost possible
+profit in selling their installations. Prices charged
+will necessarily vary with the quality of material employed,
+the care taken in constructing the engine and
+generator, the number of apparatus of the same type
+which are manufactured, the arrangement of the parts
+and that of the installations. Since there is considerable
+rivalry among gas-engine builders, selling prices are
+often cut down so far that little or no profit is left. It
+is very difficult&mdash;indeed impossible&mdash;to convince a purchaser
+that it is to his interest to pay a fair price in order
+to obtain a good installation, especially when other
+manufacturers are offering the same installation at a less
+price with the same warranties. As a result of this state
+of affairs, engine builders, in order that they may not
+lose an order, are willing, to reduce their prices, hoping
+<!--282.png--><span class='pagenum'><a name="Page_282" id="Page_282">[282]</a></span>
+to make up in the quality of the workmanship and the
+material what they would otherwise lose. Often they
+will deliver an engine too small in size but operating at
+a higher speed than that ordered; or they will select an
+old type, or carry out certain details with no great care.</p>
+
+<p>This, to be sure, is not always the case; for there are
+a few builders of engines who place their reputation
+above everything else and who would rather lose an
+order than execute it badly. Others, unfortunately,
+prefer to have the order at all costs.</p>
+
+<p>By retaining a consulting engineer, all these difficulties
+are overcome. In the first place, the engineer
+draws up a scale of prices and specifications which must
+be complied with in their entirety as well as in all details.
+Rival engine builders are thus compelled to
+make their estimates according to the same standard,
+so that one engine can readily be compared with another
+with the utmost fairness. In these specifications,
+penalties will be provided for by the engineer which
+will be levied if the warranties of the maker are not fulfilled.
+Otherwise the warranties are worth nothing.</p>
+
+<p>The first consequence of engaging a consulting engineer
+is to render the matter of cost a secondary one.
+A factory owner who employs a consulting engineer
+and pays him for his services, is impelled chiefly by the
+desire to obtain a good installation which will perform
+what he expects of it. For that reason necessary sacrifices
+will be made to comply with the client's wishes.</p>
+
+<p>If the purchaser considers the question of cost most
+important to him, he need not engage an expert to
+<!--283.png--><span class='pagenum'><a name="Page_283" id="Page_283">[283]</a></span>
+supervise the installation of his engines. He has simply
+to pick out the cheapest engine. Unfortunately, however,
+the money which he will save by such a procedure
+will be more than compensated for by the trouble which
+he will later experience when his motor stops or when
+it breaks down, because it has been cheaply built in the
+first place.</p>
+
+<p>The advice of a consulting engineer is therefore of
+importance to the purchaser, because an engine will be
+installed which will in every way meet his requirements.
+The gas-engine builder will also prefer to deal
+with an engineer, because the engineer can appreciate
+at their true worth good material and good workmanship
+and place a fair valuation upon them. The specifications
+of a gas-engine and gas-producer expert are accepted
+by most engine builders, because an expert will
+not introduce conditions which cannot be fulfilled.
+Some manufacturers refuse to consider the conditions
+imposed by specifications seriously, or else they fix different
+prices and make tenders on the basis of these
+with or without specifications. In either case the purchaser
+may be sure that he is not receiving what he has
+a right to exact.</p>
+
+<p><b>Testing the Plant.&mdash;</b>When the engine has been
+selected the consulting engineer supervises its installation,
+and, after this is completed, carries out tests in
+order to determine whether or not the guaranteed
+power and consumption are attained. The methods
+employed in testing a gas-engine are both complex and
+delicate. The quality of the gas, the proportions of the
+<!--284.png--><span class='pagenum'><a name="Page_284" id="Page_284">[284]</a></span>
+elements forming the mixture, the time and the method
+of ignition, the temperature of the cylinder-walls, the
+temperature and the pressure of the gas drawn into the
+cylinder, all these are factors which have a decided
+bearing upon the results of a test. If these factors be
+not carefully considered the conclusions to be drawn
+from the test may be absolutely wrong.</p>
+
+<p>Indicators of any type should not be indiscriminately
+employed; only those specially designed for gas-engine
+purposes should be used. Indicator cards are in themselves
+inadequate, and should be supplemented by the
+records of explosion-recorders.</p>
+
+<p>The calorific value of the gas should be measured
+either by the Witz apparatus or by means of any other
+calorimeter.</p>
+
+<p>In interpreting the diagrams and records some difficulty
+will be encountered. Sometimes it happens that
+a particular form of curve is attributed to a cause entirely
+different from the real one. It happens not infrequently
+that engineers, whose experience is confined to
+engines of one make and who have not had the opportunity
+to make sufficient comparisons, draw such erroneous
+conclusions from cards.</p>
+
+<p>To recapitulate what has already been said, the testing
+of gas-engines requires considerable experience and
+cannot be lightly undertaken. Special instruments of
+precision are necessary. The author has very often been
+called upon to contradict the results obtained by experts
+whose tests have consisted simply in ascertaining
+the engine power either by means of a Prony brake, or
+<!--285.png--><span class='pagenum'><a name="Page_285" id="Page_285">[285]</a></span>
+by means of a brake-strap on the fly-wheel. The brake
+gives but crude results at best; it is a means of control,
+and not an instrument of scientific investigation.</p>
+
+<p>Something more than the mere power produced by
+an engine should be ascertained. The tests made should
+throw some light upon the reasons why that power cannot
+be exceeded, and show that the necessary changes
+can be made to cause the engine to operate more economically
+and to yield energy of an amount which its
+owner has a right to expect. The indicator and the
+recorder are testing instruments which clearly indicate
+discrepancies in operation and the means by which they
+may be corrected. The tests made should determine
+whether the power developed is not obtained largely by
+means of controlling devices which cause premature
+wearing away of the engine parts.</p>
+
+<p>It is not the intention of the author to describe indicators
+of the well-known Watt type. It is simply his purpose
+to call attention to the explosion-recorder which
+he has devised to supplement the data obtained by
+means of the indicator.</p>
+
+<!--286.png--><p><span class='pagenum'>286</span></p>
+<div class="figcenter" style="width: 275px;">
+<img src="images/fig_145.jpg" width="275" height="600" alt="Fig. 145." title="" />
+<span class="caption"><span class='smcap'>Fig. 145.</span>&mdash;Mathot explosion-recorder.</span>
+</div>
+
+<p><b>Explosion-Recorder for Industrial Engines.&mdash;</b>The
+explosion-recorder illustrated in Fig. 145 can be
+adapted to any ordinary indicator. It is composed of
+a supporting bracket <i>B</i> upon which a drum <i>T</i> is
+mounted. This drum is rotated by a clock-train, the
+speed of which is controlled by means of a special compensating
+governor. The entire system is pivotally
+mounted upon the supporting screw <i>O</i>, so that the drum
+<i>T</i>, about which a band of paper is wound, may be
+<!--287.png--><span class='pagenum'>287</span>
+swung against a stylus <i>C</i>, which records upon the paper
+the number and power of the explosions. These explosions
+are measured according to scale by a spring connected
+with an indicator. The records obtained disclose
+for any given cycle the amount of compression as
+well as the force of the explosion, and render it possible
+to study the phenomena of expansion, exhaust, and suction.
+They are, however, inadequate in showing exactly
+how an engine runs in general. Indeed, in most
+gas-engines, as well as oil and volatile hydrocarbon engines,
+each explosion differs from that which follows in
+character and in power; and it is absolutely essential to
+provide some means of avoiding these variations. The
+explosion-recorder gives a graphic record from which
+the number of explosions can be read, and also the initial
+pressure of each explosion, the number of corresponding
+revolutions, the order in which the explosions
+succeed one another, and consequently the regularity of
+certain phenomena caused by secondary influences, such
+as the section of the distributing members, the sensitiveness
+of the governor, and the like.</p>
+
+<p>The explosion-records can be taken simultaneously
+with ordinary diagrams. In order to attain this end,
+the recorder is allowed to swing around the pivot <i>O</i>, so
+that the drum carrying the paper band is brought into
+engagement, or swung out of engagement with the
+stylus, as it is influenced by each explosion, thereby
+leaving its record on the paper. The ordinary diagram
+may be traced on the drum of the indicator, as it continues
+to operate in its usual way. Thus the explosion-recorder
+<!--288.png--><span class='pagenum'><a name="Page_288" id="Page_288">[288]</a></span>
+renders it possible to control the operation of
+engines, to obtain some idea of the cause of defects and
+to attribute them to the proper force. Improvements
+can then be made which will ensure a greater efficiency.
+A number of records herewith reproduced illustrate the
+defects in the controlling apparatus and in the construction
+of certain engines, and also the result of improvements
+which have been made on the basis of the records
+obtained. The smaller lines indicate the compression,
+which is usually constant in engines in which the "hit-and-miss"
+system of governing is employed, while the
+larger lines indicate the explosions. These records are
+only part of the complete data normally drawn on the
+paper in the period of 120 seconds corresponding with
+an entire revolution of the recorder-drum.</p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_146.jpg" width="600" height="154" alt="Fig. 146." title="" />
+<span class="caption"><span class='smcap'>Fig. 146.</span>&mdash;Record with automatic starter.</span>
+</div>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_147.jpg" width="600" height="251" alt="Fig. 147." title="" />
+<span class="caption"><span class='smcap'>Fig. 147.</span>&mdash;Gas-engine running at one-half load.</span>
+</div>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_148.jpg" width="600" height="220" alt="Fig. 148." title="" />
+<span class="caption"><span class='smcap'>Fig. 148.</span>&mdash;Record made after correcting faults.</span>
+</div>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_149.jpg" width="600" height="215" alt="Fig. 149." title="" />
+<span class="caption"><span class='smcap'>Fig. 149.</span>&mdash;Record made after correcting faults.</span>
+</div>
+
+<p>The first record was taken while starting up an engine
+provided with an automatic starting device and
+supplied with explosive mixture without previous compression
+(Fig. 146). The gradual lessening of the distances
+of the ordinates or lines representing the explosions
+shows that the speed of the motor was slowly
+increasing, and also indicates the time which elapsed
+before the engine was running smoothly. The records
+that follow (Figs. 147, 148 and 149) show the results
+<!--289.png--><span class='pagenum'>289</span>
+which can be obtained with the recorder by correcting
+the errors due to faults in installing the engine and its
+accessories. The fifth record is particularly interesting
+because it shows the influence of the ignition-tube on
+the power of the deflagration of the explosive mixture
+(Fig. 150). This record was obtained with an engine
+provided with two contiguous tubes. The communication
+of each of these tubes with the explosion-chamber
+<!--290.png--><span class='pagenum'><a name="Page_290" id="Page_290">[290]</a></span>
+could be cut off at will at any moment. The last record
+(Fig. 151) was obtained at a time when the effective
+load of the engine was changed at two different intervals.
+This record shows how regularly the engine was
+running and how constant were the initial pressures.
+These pressures, however, which is the case in most
+engines, manifestly diminish when the explosions succeed
+one another without idle strokes of the piston.
+This shows, also, the influence of "scavenging" the
+products of combustion and the effect it has on the
+efficiency of explosion-engines.</p>
+
+<p><b>Analysis of the Gases.&mdash;</b>It has already been stated
+that one of the tests which should be made consists in
+measuring the calorific value of the gas. Just what the
+calorific value of the gas may be it is necessary to know
+in order to obtain some idea of the thermal efficiency of
+the installation. If a suction gas-producer be employed
+(an apparatus in which the nature of the gas generated
+changes at each instant), calorimetrical analyses are indispensable
+in appreciating the conditions under which
+a generator operates.</p>
+
+<p>These analyses are made by means of calorimeters
+which give the calorific value either at a constant
+pressure or at a constant volume.</p>
+
+<p>Constant-volume instruments give a somewhat
+weaker record than constant-pressure instruments; but
+according to Professor Aim&eacute; Witz, the inventor of an
+excellent calorimeter, the constant-volume type is almost
+indispensable in gaging the efficiency of explosion-engines.
+<!--291.png--><span class='pagenum'>291</span></p>
+
+<div class="figcenter" style="width: 600px;">
+<img src="images/fig_150.jpg" width="600" height="212" alt="Fig. 150." title="" />
+<span class="caption"><span class='smcap'>Fig. 150.</span></span>
+</div>
+
+<div class="figcenter" style="width: 400px;">
+<img src="images/fig_150b.jpg" width="400" height="311" alt="Fig. 150b." title="" />
+<span class="caption"><span class='smcap'>Fig. 150</span><i>b</i>.</span>
+</div>
+
+<div class="figcenter" style="width: 960px;">
+<img src="images/fig_151.jpg" width="960" height="221" alt="Fig. 151." title="" />
+<span class="caption"><span class='smcap'>Fig. 151.</span>&mdash;Record made when effective load was
+changed at two different intervals.</span>
+</div>
+<!--292.png--><p><span class='pagenum'><a name="Page_292" id="Page_292">[292]</a></span></p>
+
+<div class="figcenter" style="width: 475px;">
+<img src="images/fig_152.jpg" width="475" height="500" alt="Fig. 152." title="" />
+<span class="caption"><span class='smcap'>Fig. 152.</span>&mdash;The Witz calorimeter.</span>
+</div>
+
+<p><b>The Witz Calorimeter.&mdash;</b>The accompanying diagram
+(Fig. 152) illustrates Professor Witz's instrument.
+Its elements are a steel cylinder having an interior
+diameter of 2.36 inches, about a thickness of 0.078
+inch and a height of about 3.54 inches, so that its capacity
+is about 15.1 cubic inches, and two covers screwed
+on the cylinder to seal it hermetically, oiled paper being
+used as a washer. The upper cover carries a spark-exciter;
+the lower cover is provided with a valve which
+discharges into a cylindrical member 1.06 inches in
+diameter. This second cover is downwardly inclined
+at its circumference toward the center to insure complete
+drainage of the mercury used for charging the
+calorimeter. All surfaces are nickel plated. The
+proportions of nickel and of steel are fixed by the
+manufacturer so as to render it possible to calculate the
+displacement of the apparatus in water. The calorimeter
+having been completely filled with mercury is
+inverted in this liquid in the manner of a test tube. The
+<!--293.png--><span class='pagenum'>293</span>
+explosive mixture is then introduced, being fed from
+a bell in which it has previously been prepared. A
+rubber tube connects the bell with the instrument.
+The gas is forced from the bell to the calorimeter by
+the pressure in the bell. The conical form of the bottom
+causes the calorimeter to be emptied rapidly and
+to be refilled completely with explosive gas at a pressure
+slightly above that of the atmosphere. Equilibrium
+is re-established by manipulating the valve,
+during a very short interval, so as to permit the excess
+gas to escape. During this operation the calorimeter
+must be maintained in the vertical position shown in the
+diagram. The atmospheric pressure is read off to one-tenth
+of a millimeter (0.003936 inches) on a barometer.
+The temperature of the gas may be taken to be that of
+the mercury-vessel.</p>
+
+<p>The explosive mixture is prepared in the water reservoir,
+the glass bulb shown in the accompanying illustration
+being employed. This bulb is closed at its
+upper end by means of a cock and is tapered at its lower
+end. The gas or air enters at the top by means of a
+rubber tube and gradually displaces the water through
+the lower end. The bulbs have a volume varying from
+200 to 500 cubic centimeters (12 to 30 cubic inches),
+and the error resulting from each filling of a bulb is
+certainly less than 15 cubic millimeters (0.0009 cubic
+inches). The contents are emptied into a bell by lowering
+the bulb into the water and opening the cock. If
+seven bulbfuls of air be mixed with one bulbful of gas,
+an explosive mixture of 1 to 7 is produced, this being
+<!--294.png--><span class='pagenum'>294</span>
+the proportion commonly employed for street-gas. For
+producer-gases the preferred proportion is 1 to 1, oxygen
+being often added to the air in order to insure complete
+combustion.</p>
+
+<p>The calorimeter, after having been filled, is placed
+in a vessel containing a liter (1.7598 pints) of water
+so that it is completely immersed. A spark is then
+allowed to pass. The explosion is not accompanied by
+any noise; the temperature rises a fixed number of
+degrees, so that the quantity of heat liberated can
+easily be computed. Each division of the thermometer
+is equal to 0.01502 C. The scale reading is minute,
+each interval being divided by ten, so that readings to
+the 1,500th part of a degree can be taken.</p>
+
+<p>It should be observed that the mixture generated in
+the reservoir is saturated with water vapor at the temperature
+of the reservoir. Consequently, the vapor
+generated by the explosion must condense in the calorimeter
+if the final temperature of the calorimeter is the
+same as that of the water reservoir. If, on the other
+hand, the temperature be slightly different, a correction
+must be made; but the error is negligible for differences
+in temperature of from 2 to 3 degrees C. (3.6 to
+5.4 degrees F.). This, however, is never likely to
+occur if the operation is conducted under favorable
+conditions.</p>
+
+<p>This apparatus is exceedingly simple and practical.
+It does not require the manipulation of a pump. The
+pressure of the mixture is read off on the barometer; the
+calorimeter is entirely immersed in the water of the
+<!--295.png--><span class='pagenum'><a name="Page_295" id="Page_295">[295]</a></span>
+outer vessel, so that all corrections of doubtful accuracy
+are obviated. The method requires but a very slight
+correction for temperature. Air, alone or mingled with
+oxygen, or a mixture of air and oxygen, can be easily
+tested with.</p>
+
+<p><b>Maintenance of Plants.&mdash;</b>If it should be necessary
+to retain a consulting engineer to install an engine
+capable of filling all requirements, it is also necessary
+to select a careful attendant in order that the engine
+may be kept in good condition. It is a rather widespread
+belief that a gas-engine can be operated without
+any care or inspection. This belief is all the more
+prevalent because of the employment of street-gas engines,
+which, by reason of their simplicity of construction
+and regularity of fuel supply, often run for several
+hours, and even for an entire day, without any attention
+whatever. But this negligence, particularly in the case
+of engines driven from producers, is likely to produce
+disastrous results. Although engines of this type do not
+require constant inspection during operation, still they
+require some attention in order that the speed may be
+kept at a fixed number of revolutions. Moreover,
+the care of the engine, the cleaning of the valves and of
+the various parts which are likely to become dirty, and
+the examination and cleaning of pipes, should be accomplished
+with great care and at regular intervals.
+This task should be entrusted only to a man of intelligence.
+A common workman who knows nothing of
+the care with which the parts of an engine should be
+handled is likely to do more harm than good.
+<!--296.png--><span class='pagenum'><a name="Page_296" id="Page_296">[296]</a></span></p>
+
+<p>The factory owner who follows the instructions
+which have been given in this book will avoid most of
+the stoppages and the trouble incurred in engine and
+generator installations, and may count upon a steadiness
+of operation comparable with that of a steam-engine.</p>
+
+<!--297.png-->
+
+<hr style="width: 35%;" />
+<div class='center'>
+<table border="0" cellpadding="4" cellspacing="0" summary="Stockport engine test.">
+<tr><td colspan='3'><div class="c3">TEST OF A "STOCKPORT" GAS-ENGINE WITH</div></td></tr>
+<tr><td colspan='3'><div class="c3">DOWSON PRESSURE GAS PLANT</div></td></tr>
+
+<tr><td colspan='3'><div class="c4">Made by R. Mathot at the Works of the "Union Electrique"</div></td></tr>
+<tr><td colspan='3'><div class="c4">C<sup>ie</sup>, Brussels, June 27, 1901</div></td></tr>
+
+<tr><td colspan='3'><div class="c4">Piston Diameter: 15<sup>1</sup>&frasl;<sub>2</sub>". Piston stroke, 22".</div></td></tr>
+<tr><td colspan='3'><div class="c4">Normal number of revolutions, 210.</div></td></tr>
+<tr><td align='left'>1.</td><td align='left'>Calorific value of the coal</td><td align='left'>12750 B.T.U.</td></tr>
+<tr><td align='left'>2.</td><td align='left'>Nature and origin of fuel: Anthracite coal of Charleroi (Belgium).</td></tr>
+<tr><td align='left'>3.</td><td align='left'>Cost of fuel per ton at the mine</td><td align='left'>$5.50</td></tr>
+<tr><td align='left'>4.</td><td align='left'>Cost of fuel per ton at the plant</td><td align='left'>$6.39</td></tr>
+<tr><td align='left'>5.</td><td align='left'>Fuel consumption per hour in the generator</td><td align='left'>46.3 lbs.</td></tr>
+<tr><td align='left'>6.</td><td align='left'>Fuel consumption per hour in the boiler</td><td align='left'>7 lbs.</td></tr>
+<tr><td align='left'>7.</td><td align='left'>Proportion of ash in the coal</td><td align='left'>6 per cent.</td></tr>
+<tr><td align='left'>8.</td><td align='left'>Weight of steam at 66 lbs. generated per hour</td><td align='left'>42.7 lbs.</td></tr>
+<tr><td align='left'>9.</td><td align='left'>Average brake horse-power</td><td align='left'>53 B.H.P.</td></tr>
+<tr><td align='left'>10.</td><td align='left'> Fuel consumption for gas per B.H.P. per hour</td>
+<td align='left'>0.875 lbs.</td></tr>
+<tr><td align='left'>11.</td><td align='left'> Fuel consumption for steam per B.H.P. per hour</td><td align='left'>0.133 lbs.</td></tr>
+<tr><td align='left'>12.</td><td align='left'> Total fuel consumption</td><td align='left'>1.008 lbs.</td></tr>
+<tr><td align='left'>13.</td><td align='left'> Steam consumption at 66 lbs. pressure</td><td align='left'>0.81 lbs.</td></tr>
+<tr><td align='left'>14.</td><td align='left'> Gas pressure at the engine</td><td align='left'>1<sup>3</sup>&frasl;<sub>8</sub> inches</td></tr>
+<tr><td align='left'>15.</td><td align='left'> Weight of water per B.H.P. per hour for
+cooling the cylinder entering at 68&deg; F. and leaving at 105&deg; F.</td>
+<td align='left'>51.5 lbs.</td></tr>
+<tr><td align='left'>
+<!--297.png--><span class='pagenum'><a name="Page_297" id="Page_297">[297]</a></span></td></tr>
+<tr><td align='left'>16.</td><td align='left'> Corresponding heat absorbed in cooling</td><td align='left'>1970 B.T.U.</td></tr>
+<tr><td align='left'>17.</td><td align='left'> Average initial explosive pressure on piston</td><td align='left'>324 lbs.</td></tr>
+<tr><td align='left'>18.</td><td align='left'> Average pressure on piston per square inch</td><td align='left'>72 lbs.</td></tr>
+<tr><td align='left'>19.</td><td align='left'> Average indicated horse-power with 85 per cent. misses</td>
+<td align='left'>92.5 I.H.P.</td></tr>
+<tr><td align='left'>20.</td><td align='left'> Corresponding mechanical efficiency</td><td align='left'>84 per cent.</td></tr>
+<tr><td align='left'>21.</td><td align='left'> Corresponding electric load</td><td align='left'>31.950 K.W.</td></tr>
+<tr><td align='left'>22.</td><td align='left'> Cost of B.H.P. per hour in anthracite</td><td align='left'>$0.0029</td></tr>
+<tr><td align='left'>23.</td><td align='left'> Cost of kilowatt per hour in anthracite</td><td align='left'>$0.0048</td></tr>
+<tr><td align='left'>24.</td><td align='left'> Electric power generated per B.H.P.</td><td align='left'>602.8 W.</td></tr>
+<tr><td align='left'>25.</td><td align='left'> Thermal efficiency at 53 B.H.P. with 85 per cent. explosions</td>
+<td align='left'>18.5 per cent.</td></tr>
+
+<tr><td colspan='3'><hr style="width: 35%;" /></td></tr>
+<tr><td colspan='3'><div class="c3">TEST OF A 20 H.P. WINTERTHUR ENGINE</div></td></tr>
+
+<tr><td colspan='3'><div class="c4">With Winterthur Suction-Producer made by R. Mathot</div></td></tr>
+<tr><td colspan='3'><div class="c4">at Winterthur, June 4 and 5, 1902</div></td></tr>
+
+<tr><td colspan='3'><div class="c4">DATA OF TESTS WITH ILLUMINATING GAS AND WITH FUEL GAS</div></td></tr>
+
+<tr><td colspan='3'><div class="blkquot">Dimensions of Winterthur Engine&mdash;Piston diameter: 10<sup>3</sup>&frasl;<sub>8</sub>". Stroke:
+16<sup>7</sup>&frasl;<sub>8</sub>". Compression: 177 pounds per square inch. Regulation:
+hit and miss. Ignition: electro-magnetic. Fly-wheel: normal,
+with external bearing. Lubrication of piston: with oil-pump.
+Of main bearings, with rings (as in dynamos).</div></td></tr>
+
+<tr><td colspan='3'><div class="c3">FULL LOAD WITH STREET-GAS</div></td></tr>
+
+<tr><td align='left'>1.</td><td align='left'>Number of revolutions per minute</td><td align='left'>200</td></tr>
+<tr><td align='left'>2.</td><td align='left'>Corresponding number of explosions</td><td align='left'>96 per cent.</td></tr>
+<tr><td align='left'>3.</td><td align='left'>Net load on brake</td><td align='left'>120 lbs.</td></tr>
+<tr><td align='left'>4.</td><td align='left'>Corresponding effective power</td><td align='left'>22 B.H.P.</td></tr>
+<tr><td align='left'>5.</td><td align='left'>Mean initial explosive pressure on piston per square inch</td>
+<td align='left'>455 lbs.</td></tr>
+<tr><td align='left'>6.</td><td align='left'>Average pressure on piston per square inch</td><td align='left'>78 lbs.</td></tr>
+<tr><td align='left'>7.</td><td align='left'>Gas consumption per B.H.P. at 24&deg; C. and 721 mm. mean pressure</td>
+<td align='left'>15.5 cubic feet</td></tr>
+<tr><td align='left'>8.</td><td align='left'>Gas consumption per B.H.P. reduced to 0&deg; C. and 760 mm. mean pressure</td><td align='left'>13.5 cubic feet</td></tr>
+<tr><td colspan='3'><hr style="width: 35%;" /></td></tr>
+<!--298.png--><tr><td><p><span class='pagenum'><a name="Page_298" id="Page_298">[298]</a></span></p></td></tr>
+
+<tr><td colspan='3'><div class="c3">HALF LOAD WITH STREET-GAS</div></td></tr>
+
+<tr><td align='left'>9.</td><td align='left'>Number of revolutions per minute</td><td align='left'>204</td></tr>
+<tr><td align='left'>10.</td><td align='left'>Corresponding number of explosions</td><td align='left'>60 per cent.</td></tr>
+<tr><td align='left'>11.</td><td align='left'>Net load on brake</td><td align='left'>60 lbs.</td></tr>
+<tr><td align='left'>12.</td><td align='left'>Corresponding effective power</td><td align='left'>11.6 B.H.P.</td></tr>
+<tr><td align='left'>13.</td><td align='left'>Gas consumption per B.H.P. per hour at 24&deg; C.</td></tr>
+<tr><td align='left'></td><td align='left'>and 721 mm. mean pressure.</td><td align='left'>21 cubic feet</td></tr>
+<tr><td align='left'>14.</td><td align='left'>Gas consumption per B.H.P. per hour at 0&deg; C.
+and 760 mm. mean pressure.</td><td align='left'>18.3 cubic feet</td></tr>
+
+<tr><td colspan='3'><hr style="width: 35%;" /></td></tr>
+<tr><td colspan='3'><div class="c3">RUNNING WITH NO LOAD WITH STREET-GAS</div></td></tr>
+
+<tr><td align='left'>15.</td><td align='left'>Number of revolutions per minute</td><td align='left'>206</td></tr>
+<tr><td align='left'>16.</td><td align='left'>Corresponding number of explosions</td><td align='left'>22 per cent.</td></tr>
+<tr><td align='left'>17.</td><td align='left'>Total gas consumption per hour at 24&deg; C.
+and 721 mm. mean pressure.</td><td align='left'>106 cubic feet</td></tr>
+<tr><td align='left'>18.</td><td align='left'>Maximum calorific power of gas per cubic foot</td><td align='left'>598 B.T.U.</td></tr>
+<tr><td align='left'>19.</td><td align='left'>Thermal efficiency with 96 per cent. explosions</td><td align='left'>31 per cent.</td></tr>
+<tr><td align='left'>20.</td><td align='left'>Mechanical efficiency with 96 per cent. explosions</td>
+<td align='left'>82 per cent.</td></tr>
+<tr><td align='left'>21.</td><td align='left'>Temperature of water at the jacket-inlet</td><td align='left'>75 degs. F.</td></tr>
+<tr><td align='left'>22.</td><td align='left'>Temperature of water at the jacket-outlet</td><td align='left'>130 degs. F.</td></tr>
+<tr><td align='left'>23.</td><td align='left'>Compression per square inch on piston surface</td><td align='left'>178 lbs.</td></tr>
+<tr><td align='left'>24.</td><td align='left'>Pressure after expansion</td><td align='left'>37 lbs.</td></tr>
+
+<tr><td colspan='3'><hr style="width: 35%;" /></td></tr>
+<tr><td colspan='3'><div class="c3">TEST OF WINTERTHUR PLANT WITH PRODUCER-GAS</div></td></tr>
+
+<tr><td align='left'>1.</td><td align='left'>Nature of fuel. Belgian anthracite, "Bonne Esperance et Batterie"; size,</td>
+    <td align='left'><sup>3</sup>&frasl;<sub>4</sub> inch.</td></tr>
+<tr><td align='left'>2.</td><td align='left'>Chemical composition: Carbon, 86.5 per cent.;
+    hydrogen, 3.5 per cent.; oxygen and nitrogen, 4.65 per cent.; ash, 5.35 per cent.</td></tr>
+<tr><td align='left'>
+<!--299.png--><span class='pagenum'>299</span></td></tr>
+<tr><td align='left'>3.</td><td align='left'>Calorific value per pound of coal</td><td align='left'>14200 B.T.U.</td></tr>
+<tr><td align='left'>4.</td><td align='left'>Net calorific value per pound of fuel</td><td align='left'>15050 B.T.U.</td></tr>
+<tr><td align='left'>5.</td><td align='left'>Price of anthracite delivered at the plant</td><td align='left'>$3.50 per ton</td></tr>
+<tr><td align='left'>6.</td><td align='left'>Number of revolutions of engine per minute</td><td align='left'>200</td></tr>
+<tr><td align='left'>7.</td><td align='left'>Corresponding number of explosions</td><td align='left'>91 per cent.</td></tr>
+<tr><td align='left'>8.</td><td align='left'>Load on brake&nbsp;</td><td align='left'>106 lbs.</td></tr>
+<tr><td align='left'>9.</td><td align='left'>Corresponding effective horse-power</td><td align='left'>20.2 B.H.P.</td></tr>
+<tr><td align='left'>10.</td><td align='left'>Fuel consumption at the generator per hour</td><td align='left'>16.4 lbs.</td></tr>
+<tr><td align='left'>11.</td><td align='left'>Fuel consumed per B.H.P. per hour</td><td align='left'>0.81 lbs.</td></tr>
+<tr><td align='left'>12.</td><td align='left'>Proportion of ash resulting from the tests</td><td align='left'>6 per cent.</td></tr>
+<tr><td align='left'>13.</td><td align='left'>Mean initial explosive pressure per square inch</td>
+<td align='left'>419.5 lbs.</td></tr>
+<tr><td align='left'>14.</td><td align='left'>Average pressure on piston per square inch</td><td align='left'>72.5 lbs.</td></tr>
+<tr><td align='left'>15.</td><td align='left'>Indicated horse-power with 91 per cent. explosions</td>
+<td align='left'>25.4 I.H.P.</td></tr>
+<tr><td align='left'>16.</td><td align='left'>Mechanical efficiency</td><td align='left'>79 per cent.</td></tr>
+<tr><td align='left'>17.</td><td align='left'>Thermal efficiency at the producer</td><td align='left'>22 per cent.</td></tr>
+<tr><td align='left'>18.</td><td align='left'>Water consumption per hour in the scrubber</td><td align='left'>66 gals.</td></tr>
+<tr><td align='left'>19.</td><td align='left'>Cost per B.H.P. per hour in anthracite</td><td align='left'>62 gals.</td></tr>
+
+<tr><td colspan='3'><hr style="width: 35%;" /></td></tr>
+
+<tr><td colspan='3'><div class="c3">TEST OF A 60 B.H.P. GAS-ENGINE, TYPE G 9, WITH
+A SUCTION-GAS PLANT OF THE GASMOTOREN
+FABRIK DEUTZ</div></td></tr>
+
+<tr><td colspan='3'><div class="c4">(Made at Cologne, March 15, 1904, by R. Mathot.)</div></td></tr>
+
+<tr><td colspan='3'><div class="c4">DATA OF THE TESTS</div></td></tr>
+
+<tr><td colspan='3'><div class="c4">Diameter of Piston = 16.5". Piston Stroke = 18.9"</div></td></tr>
+
+<tr><td colspan='3'><div class="c4">FULL LOAD</div></td></tr>
+
+<tr><td align='left'>1.</td><td align='left'>Average number of revolutions per minute</td><td align='left'>188.66</td></tr>
+<tr><td align='left'>2.</td><td align='left'>Corresponding effective work</td><td align='left'>65.11 B.H.P.</td></tr>
+<tr><td align='left'>3.</td><td align='left'>Average compression per square inch</td><td align='left'>176 lbs.</td></tr>
+<tr><td align='left'>4.</td><td align='left'>Average initial explosive pressure per square inch&nbsp;</td>
+<td align='left'>397 lbs.</td></tr>
+<tr><td align='left'>5.</td><td align='left'>Average final expansion pressure</td><td align='left'>25 lbs.</td></tr>
+<tr><td align='left'>6.</td><td align='left'>Vacuum at suction</td><td align='left'>4.4 lbs.</td></tr>
+<tr><td align='left'>7.</td><td align='left'>Average pressure on piston</td><td align='left'>81 lbs.</td></tr>
+<tr><td align='left'>8.</td><td align='left'>Corresponding indicated horse-power</td><td align='left'>77 I.H.P.</td></tr>
+<tr><td>
+<!--300.png--><span class='pagenum'>300</span></td></tr>
+<tr><td colspan='3'><hr style="width: 35%;" /></td></tr>
+
+<tr><td colspan='3'><div class="c3">FUEL</div></td></tr>
+
+<tr><td align='left'>9.</td><td align='left'>Nature of fuel: Anthracite coal 0.4" to 0.8"</td></tr>
+<tr><td align='left'>10.</td><td align='left'>Origin: Coalpit of Zeihe, Morsbach at Aix-la-Chapelle.</td></tr>
+<tr><td align='left'>11.</td><td align='left'>Chemical composition of coal:</td></tr>
+<tr><td align='left'></td><td align='left'>Carbon</td><td align='left'>83.22%</td></tr>
+<tr><td align='left'></td><td align='left'>Hydrogen</td><td align='left'>3.31%</td></tr>
+<tr><td align='left'></td><td align='left'>Nitrogen and Oxygen</td><td align='left'>3.01%</td></tr>
+<tr><td align='left'></td><td align='left'>Sulphur</td><td align='left'>0.44%</td></tr>
+<tr><td align='left'></td><td align='left'>Ash</td><td align='left'>7.33%</td></tr>
+<tr><td align='left'></td><td align='left'>Water</td><td align='left'>2.69%</td></tr>
+<tr><td align='left'>12.</td><td align='left'>Calorific value.</td><td align='left'>13650 B.T.U.</td></tr>
+
+<tr><td colspan='3'><hr style="width: 35%;" /></td></tr>
+<tr><td colspan='3'><div class="c3">GAS</div></td></tr>
+
+<tr><td align='left'>13.</td><td align='left'>Chemical composition of gas:</td></tr>
+<tr><td align='left'>Carbonic acid</td><td align='left'>6.60%</td></tr>
+<tr><td align='left'>Oxygen</td><td align='left'>0.30%</td></tr>
+<tr><td align='left'>Hydrogen</td><td align='left'>18.90%</td></tr>
+<tr><td align='left'>Methane</td><td align='left'>0.57%</td></tr>
+<tr><td align='left'>Carbon monoxide</td><td align='left'>24.30%</td></tr>
+<tr><td align='left'>Nitrogen</td><td align='left'>49.33%</td></tr>
+<tr><td align='left'>14.</td><td align='left'> Calorific value of gas, combination water, at 59&deg; F. constant
+volume reduced to 32&deg; F. and atmospheric pressure</td><td align='left'>140 B.T.U.</td></tr>
+
+<tr><td colspan='3'><hr style="width: 35%;" /></td></tr>
+<tr><td colspan='3'><div class="c3">TEMPERATURES</div></td></tr>
+
+<tr><td colspan='3'><div class="c3"><i>Engine</i></div></td></tr>
+
+<tr><td align='left'>15.</td><td align='left'>Cooling water at the inlet of the cylinder-head</td>
+<td align='left'>55.4 deg. F.</td></tr>
+<tr><td align='left'></td><td align='left'>&nbsp;&nbsp;&nbsp;Temperature at the outlet</td><td align='left'>109.5 deg. F.</td></tr>
+<tr><td align='left'>16.</td><td align='left'> Temperature at outlet of cylinder</td><td align='left'>127.5 deg. F.</td></tr>
+
+<tr><td colspan='3'><hr style="width: 35%;" /></td></tr>
+<tr><td colspan='3'><div class="c3"><i>Gas-Generator</i></div></td></tr>
+
+<tr><td align='left'>17.</td><td align='left'>Temperature of water in the vaporizer</td><td align='left'>158.3 deg. F.</td></tr>
+
+<tr><td colspan='3'><hr style="width: 35%;" /></td></tr>
+<tr><td colspan='3'><div class="c3">EFFICIENCIES AND CONSUMPTION</div></td></tr>
+
+<tr><td align='left'>18.</td><td align='left'>Mechanical efficiency</td><td align='left'>84.6%</td></tr>
+<tr><td align='left'>19.</td><td align='left'>Gross consumption of coal per B.H.P. per hour</td><td align='left'>0.86 lbs</td></tr>
+<tr><td align='left'>20.</td><td align='left'>Thermal efficiency in proportion to the effective work
+and the gross consumption of coal in the gas-generator</td><td align='left'> 24.3%</td></tr>
+
+<!--301.png--><tr><td><p><span class='pagenum'>301</span></p></td></tr>
+<tr><td colspan='3'><hr style="width: 35%;" /></td></tr>
+<tr><td colspan='3'><div class="c3">HALF LOAD</div></td></tr>
+
+<tr><td colspan='3'><div class="c3">WORK</div></td></tr>
+
+<tr><td align='left'>1.</td><td align='left'>Average number of revolutions per minute</td><td align='left'>195.5</td></tr>
+<tr><td align='left'>2.</td><td align='left'>Corresponding effective work</td><td align='left'>33.85 B.H.P.</td></tr>
+<tr><td align='left'>3.</td><td align='left'>Corresponding average compression</td><td align='left'>125 lbs.</td></tr>
+<tr><td align='left'>4.</td><td align='left'>Average initial explosive pressure</td><td align='left'>258 lbs.</td></tr>
+<tr><td align='left'>5.</td><td align='left'>Average final expansion</td><td align='left'>18 lbs.</td></tr>
+<tr><td align='left'>6.</td><td align='left'>Vacuum at suction</td><td align='left'>6.8 lbs.</td></tr>
+<tr><td align='left'>7.</td><td align='left'>Average mean pressure on piston</td><td align='left'>46.2 lbs.</td></tr>
+<tr><td align='left'>8.</td><td align='left'>Corresponding indicated power</td><td align='left'>45. I.H.P.</td></tr>
+<tr><td align='left'>9.</td><td align='left'>Speed variation between full and half load</td><td align='left'>3.5%</td></tr>
+
+<tr><td colspan='3'><hr style="width: 35%;" /></td></tr>
+<tr><td colspan='3'><div class="c3">CONSUMPTION</div></td></tr>
+
+<tr><td align='left'>10.</td><td align='left'>Gross consumption of coal per B.H.P. per hour</td><td align='left'>1.155 lbs.</td></tr>
+
+<tr><td colspan='3'><hr style="width: 35%;" /></td></tr>
+<tr><td colspan='3'><div class="c3">RUNNING WITH NO LOAD</div></td></tr>
+
+<tr><td align='left'>1.</td><td align='left'>Average number of revolutions per minute</td><td align='left'>199</td></tr>
+<tr><td align='left'>2.</td><td align='left'>Minimum corresponding compression</td><td align='left'>95.55 lbs.</td></tr>
+<tr><td align='left'>3.</td><td align='left'>Average initial explosive pressure</td><td align='left'>220 lbs.</td></tr>
+<tr><td align='left'>4.</td><td align='left'>Average final expansion</td><td align='left'>0 lbs.</td></tr>
+<tr><td align='left'>5.</td><td align='left'>Vacuum at suction</td><td align='left'>8.8 lbs.</td></tr>
+<tr><td align='left'>6.</td><td align='left'>Average pressure on piston</td><td align='left'>11.2 lbs.</td></tr>
+<tr><td align='left'>7.</td><td align='left'>Corresponding indicated horse-power.</td><td align='left'>11 I.H.P.</td></tr>
+<tr><td align='left'>8.</td><td align='left'>Speed variation between full load and no load</td><td align='left'>5.2%</td></tr>
+
+<tr><td colspan='3'><hr style="width: 35%;" /></td></tr>
+<tr><td colspan='3'><div class="c3">TEST OF A GAS PLANT OF A FOUR-CYCLE DOUBLE-ACTING
+ENGINE OF 200 H.P. AND A SUCTION-PRODUCER
+IN THE WORKS OF THE GASMOTOREN
+FABRIK DEUTZ, COLOGNE</div></td></tr>
+
+<tr><td colspan='3'><div class="c4">March 14 and 15, 1904, by Messrs. A. Witz, R. Mathot, and de
+Herbais</div></td></tr>
+
+<tr><td colspan='3'><div class="c3">DATA OF THE TESTS</div></td></tr>
+
+<tr><td colspan='3'><div class="blkquot">Piston Diameter: 21<sup>1</sup>&frasl;<sub>4</sub>". Stroke: 27<sup>9</sup>&frasl;<sub>16</sub>". Diameter of Piston-Rods:
+front, 4<sup>3</sup>&frasl;<sub>4</sub>"; rear, 4<sup>5</sup>&frasl;<sub>16</sub>"</div></td></tr>
+
+<tr><td><!--302.png--><p><span class='pagenum'>302</span></p></td></tr>
+
+<tr><td colspan='3'><div class="c3">ENGINE</div></td></tr>
+
+<tr><td colspan='3'><div class="c3"><i>Full Load Tests</i></div></td></tr>
+
+<tr><td align='left'>1.</td><td align='left'>Average number of revolutions per minute</td><td align='left'>151.29 and 150.20</td></tr>
+<tr><td align='left'>2.</td><td align='left'>Corresponding effective load</td><td align='left'>214.22 B.H.P.
+and 222.83 B.H.P.</td></tr>
+<tr><td align='left'>3.</td><td align='left'>Duration of the tests</td><td align='left'>3 hours and 10 hours</td></tr>
+<tr><td align='left'>4.</td><td align='left'>Average temperature of water after cooling the piston</td>
+<td align='left'>117.5 deg. F.</td></tr>
+<tr><td align='left'>5.</td><td align='left'>Average temperature of water after cooling the cylinder and valve-seats</td>
+<td align='left'>135 deg. F.</td></tr>
+<tr><td align='left'>6.</td><td align='left'>Water consumption per hour for cooling the piston</td><td align='left'>39 gal.</td></tr>
+
+<tr><td colspan='3'><hr style="width: 35%;" /></td></tr>
+<tr><td colspan='3'><div class="c3">PRODUCER</div></td></tr>
+
+<tr><td align='left'>7.</td><td align='left'>Nature and Origin of Fuel: Anthracite coal
+"Bonne-Esperance et Batterie" Herstal, Belgium.</td></tr>
+<tr><td align='left'>8.</td><td align='left'>Calorific value of fuel</td><td align='left'>14650 B.T.U.</td></tr>
+<tr><td align='left'>9.</td><td align='left'>Consumption of fuel per hour (plus 53 lbs.
+on the night of the 14th for keeping the generator fired during 14 hours, the
+engine being stopped)</td><td align='left'>199 lbs.-160 lbs.</td></tr>
+<tr><td align='left'>10.</td><td align='left'>Water consumption per hour in the vaporiser</td><td align='left'>14.2 gals.</td></tr>
+<tr><td align='left'>11.</td><td align='left'>Water consumption per hour in the scrubbers</td><td align='left'>318 gals.</td></tr>
+<tr><td align='left'>12.</td><td align='left'>Average temperature of gas at the outlet of the generator</td>
+<td align='left'>558 deg. F.</td></tr>
+<tr><td align='left'>13.</td><td align='left'>Average temperature of gas at the outlet of the scrubbers</td>
+<td align='left'>62.5 deg. F.</td></tr>
+
+<tr><td colspan='3'><hr style="width: 35%;" /></td></tr>
+<tr><td colspan='3'><div class="c3">EFFICIENCIES</div></td></tr>
+
+<tr><td align='left'>14.</td><td align='left'>Gross consumption of coal per B.H.P. per hour</td><td align='left'>0.927 lbs.-0.720 lbs.</td></tr>
+<tr><td align='left'>15.</td><td align='left'>Consumption of coal per B.H.P. after deduction of the water</td>
+<td align='left'>0.907 lbs.-0.705 lbs.</td></tr>
+<tr><td><!--303.png--><span class='pagenum'>303</span></td></tr>
+<!--303.png-->
+<tr><td align='left'>16.</td><td align='left'>Thermal efficiency relating to the
+effective H.P. and to the dry coal consumed in the generator</td><td align='left'>19%-24.4%</td></tr>
+<tr><td align='left'>17.</td><td align='left'>Water consumption per B.H.P. hour:</td></tr>
+<tr><td align='left'></td><td align='left'>For the cylinder, stuffing-boxes and valve-seat jackets</td>
+<td align='left'>4.65 gals.</td></tr>
+<tr><td align='left'></td><td align='left'>For the piston and piston-rods</td><td align='left'>1.75 gals.</td></tr>
+<tr><td align='left'></td><td align='left'>For the vaporizer</td><td align='left'>0.0655 gals.</td></tr>
+<tr><td align='left'></td><td align='left'>For washing the gas in the scrubbers</td><td align='left'>1.42 gals.</td></tr>
+<tr><td align='left'>18.</td><td align='left'>Water converted in steam per lb. consumed in the generator</td>
+<td align='left'>0.193 gals.</td></tr>
+</table></div>
+<hr style="width: 95%;" />
+<!--305.png--><p><span class='pagenum'>305</span></p>
+
+<h2>INDEX</h2>
+
+<dl>
+
+<dt class="indexsubhdr">A</dt>
+
+<dt>Adjustment of gas-engine, <a href="#Page_126">126</a></dt>
+
+<dt>Adjustment of moving parts, imperfect, <a href="#Page_146">146</a></dt>
+
+<dt>Admission-valve, binding of, <a href="#Page_152">152</a></dt>
+
+<dt>Admission, variable, <a href="#Page_55">55</a>, <a href="#Page_56">56</a></dt>
+
+<dt>Air-blast, <a href="#Page_180">180</a></dt>
+
+<dt>Air-chest, <a href="#Page_82">82</a></dt>
+
+<dt>Air, displacement of, <a href="#Page_92">92</a></dt>
+
+<dt>Air, exclusion of, in producers, <a href="#Page_207">207</a></dt>
+
+<dt>Air, filtration of, <a href="#Page_82">82</a></dt>
+
+<dt>Air-heater, Winterthur, <a href="#Page_236">236</a></dt>
+
+<dt>Air-heaters, <a href="#Page_238">238</a></dt>
+
+<dt>Air-pipe, <a href="#Page_82">82</a></dt>
+
+<dt>Air-pipe, location of, <a href="#Page_83">83</a></dt>
+
+<dt>Air-pump, <a href="#Page_266">266</a></dt>
+
+<dt>Air, regulation of supply, <a href="#Page_82">82</a></dt>
+
+<dt>Air suction, <a href="#Page_81">81</a></dt>
+
+<dt>Air suction, resistance to, <a href="#Page_82">82</a></dt>
+
+<dt>Air supply of producer, <a href="#Page_225">225</a></dt>
+
+<dt>Air-valve, control by engine, <a href="#Page_25">25</a></dt>
+
+<dt>Air vibration, <a href="#Page_92">92</a></dt>
+
+<dt>Alcohol as engine fuel, <a href="#Page_264">264</a></dt>
+
+<dt>Anthracite, consumption of, in producers, <a href="#Page_200">200</a></dt>
+
+<dt>Anthracite in producers, <a href="#Page_190">190</a>, <a href="#Page_201">201</a></dt>
+
+<dt>Anti-pulsators, <a href="#Page_77">77</a></dt>
+
+<dt>Anti-pulsators, disconnection of, in stopping engine, <a href="#Page_132">132</a></dt>
+
+<dt>Anti-pulsators, precautions to be taken with, <a href="#Page_79">79</a></dt>
+
+<dt>Anti-vibratory substances, <a href="#Page_89">89</a></dt>
+
+<dt>Ash-pit, <a href="#Page_214">214</a>, <a href="#Page_217">217</a></dt>
+
+<dt>Ash-pit, Bollinckx, <a href="#Page_220">220</a></dt>
+
+<dt>Ash-pit, cleaning of, <a href="#Page_261">261</a></dt>
+
+<dt>Ash-pit, Deutz, <a href="#Page_220">220</a></dt>
+
+<dt>Ash-pit, door of, <a href="#Page_220">220</a></dt>
+
+<dt>Ash-pit, Wiedenfeld, <a href="#Page_220">220</a></dt>
+
+<dt>Asphyxiation, <a href="#Page_169">169</a></dt>
+
+<dt>Atomizer of oil-engines, <a href="#Page_265">265</a></dt>
+
+<dt class="indexsubhdr">B</dt>
+
+<dt>Back firing, <a href="#Page_82">82</a>, <a href="#Page_131">131</a></dt>
+
+<dt>Back pressure to exhaust, <a href="#Page_151">151</a></dt>
+
+<dt>Bags, arrangement of, <a href="#Page_80">80</a></dt>
+
+<dt>Bags, capacity of, <a href="#Page_79">79</a></dt>
+
+<dt>Bags, precautions to be taken with, <a href="#Page_79">79</a></dt>
+
+<dt>Bags, rubber, <a href="#Page_77">77</a></dt>
+
+<dt>Bark as producer fuel, <a href="#Page_193">193</a></dt>
+
+<dt>Batteries for ignition, <a href="#Page_31">31</a></dt>
+
+<dt>Bearings, adjustability of, <a href="#Page_5">5</a></dt>
+
+<dt>Bearings, adjustment of, <a href="#Page_44">44</a></dt>
+
+<dt>Bearings, care of, <a href="#Page_123">123</a></dt>
+
+<dt>Bearings, lubrication of, <a href="#Page_117">117</a></dt>
+
+<dt>Bearings, material of, <a href="#Page_51">51</a></dt>
+
+<dt>Bearings of fly-wheels, <a href="#Page_92">92</a></dt>
+
+<dt>Bearings, overheated, <a href="#Page_146">146</a></dt>
+
+<dt>Bearings, over-lubricated, <a href="#Page_150">150</a></dt>
+
+<dt>Bearings, position of, <a href="#Page_44">44</a></dt>
+
+<dt>Bell, gas-holder, <a href="#Page_187">187</a></dt>
+
+<dt>Bell, Pintsch, <a href="#Page_248">248</a></dt>
+
+<dt>Bell, volume of, <a href="#Page_187">187</a></dt>
+
+<dt>Belts, prevention of adhesion by oil, <a href="#Page_120">120</a></dt>
+
+<dt>B&eacute;nier, E., <a href="#Page_199">199</a></dt>
+
+<dt>Benzin as engine fuel, <a href="#Page_264">264</a></dt>
+
+<dt>Binding, <a href="#Page_147">147</a></dt>
+
+<dt>Blast in producers, <a href="#Page_180">180</a>, <a href="#Page_193">193</a>, <a href="#Page_225">225</a></dt>
+
+<dt>Blower, Koerting, <a href="#Page_181">181</a></dt>
+
+<dt>Blower, Root, <a href="#Page_182">182</a>, <a href="#Page_188">188</a></dt>
+
+<dt>Blowers for producers, <a href="#Page_181">181</a></dt>
+
+<dt>Blowing-generators, <a href="#Page_169">169</a></dt>
+
+<dt>Bolts of foundation, <a href="#Page_91">91</a></dt>
+
+<dt>Bomb, Witz, <a href="#Page_284">284</a>, <a href="#Page_292">292</a></dt>
+
+<dt>Boughs for coolers, <a href="#Page_108">108</a></dt>
+
+<dt>Box, charging, <a href="#Page_221">221</a></dt>
+
+<dt>Box, double closure for charging, <a href="#Page_222">222</a></dt>
+
+<dt>Box, removable charging, <a href="#Page_225">225</a></dt>
+
+<dt>Brake tests, <a href="#Page_284">284</a></dt>
+
+<dt>Branch pipes, minimum diameter of, <a href="#Page_81">81</a></dt>
+
+<dt>Bricks for foundation, <a href="#Page_91">91</a></dt>
+
+<dt>Brushes, lifting of, when dynamo-engine is stopped, <a href="#Page_132">132</a></dt>
+
+<dt>Brush, purifying, <a href="#Page_250">250</a></dt>
+
+<dt>Burner of hot tube, how ignited, <a href="#Page_128">128</a></dt>
+
+<dt>Burner, regulation of fixed, <a href="#Page_144">144</a></dt>
+
+<dt>Bushings, care of, <a href="#Page_123">123</a></dt>
+
+<dt>Bushings, fusion of, <a href="#Page_147">147</a></dt>
+
+<dt>Bushings (see also Bearings)
+
+<!--306.png--><span class='pagenum'>306</span></dt>
+
+<dt class="indexsubhdr">C</dt>
+
+<dt>Calorimeter, Witz, <a href="#Page_292">292</a></dt>
+
+<dt>Calorimeters, <a href="#Page_284">284</a>, <a href="#Page_290">290</a></dt>
+
+<dt>Cam, half-compression, <a href="#Page_130">130</a>, <a href="#Page_132">132</a></dt>
+
+<dt>Cam, relief, <a href="#Page_130">130</a></dt>
+
+<dt>Cams, <a href="#Page_51">51</a></dt>
+
+<dt>Caps of valve-chests, <a href="#Page_124">124</a></dt>
+
+<dt>Carbureter, <a href="#Page_266">266</a></dt>
+
+<dt>Care during operation of engine, <a href="#Page_131">131</a></dt>
+
+<dt>Casing, independence of frame, <a href="#Page_42">42</a></dt>
+
+<dt>Charging a producer, <a href="#Page_221">221</a></dt>
+
+<dt>Charging the generator, <a href="#Page_259">259</a></dt>
+
+<dt>Chest for exhaust, <a href="#Page_83">83</a></dt>
+
+<dt>Circulation of water, <a href="#Page_98">98</a>, <a href="#Page_125">125</a></dt>
+
+<dt>Circulation of water, how effected, <a href="#Page_102">102</a></dt>
+
+<dt>Circulation of water in tanks, <a href="#Page_105">105</a></dt>
+
+<dt>Circulation of water, regulation of, <a href="#Page_107">107</a></dt>
+
+<dt>Cleaning of producer, <a href="#Page_261">261</a></dt>
+
+<dt>Cleanliness, necessity of, <a href="#Page_121">121</a></dt>
+
+<dt>Cleanliness of producers, <a href="#Page_179">179</a></dt>
+
+<dt>Closures for charging-boxes, <a href="#Page_223">223</a></dt>
+
+<dt>Coal in producers, <a href="#Page_201">201</a></dt>
+
+<dt>Coal in producers, bituminous, <a href="#Page_195">195</a></dt>
+
+<dt>Coal, Pennsylvania, <a href="#Page_203">203</a></dt>
+
+<dt>Coal (see also Anthracite)</dt>
+
+<dt>Coal, Welsh, <a href="#Page_203">203</a></dt>
+
+<dt>Cock, Deutz, <a href="#Page_224">224</a></dt>
+
+<dt>Cock, Pierson, <a href="#Page_224">224</a></dt>
+
+<dt>Cock for charging-box, <a href="#Page_223">223</a>, <a href="#Page_224">224</a></dt>
+
+<dt>Coke in producers, <a href="#Page_201">201</a></dt>
+
+<dt>Coke in washers, <a href="#Page_242">242</a></dt>
+
+<dt>Combustion-generators, <a href="#Page_193">193</a></dt>
+
+<dt>Combustion, inverted, <a href="#Page_195">195</a></dt>
+
+<dt>Compression, determination of, <a href="#Page_273">273</a></dt>
+
+<dt>Compression, faulty, <a href="#Page_134">134</a></dt>
+
+<dt>Compression, high, <a href="#Page_154">154</a></dt>
+
+<dt>Compression in Banki engine, <a href="#Page_264">264</a></dt>
+
+<dt>Compression in Diesel engine, <a href="#Page_264">264</a></dt>
+
+<dt>Compression, losses in, <a href="#Page_143">143</a></dt>
+
+<dt>Compression period, <a href="#Page_21">21</a></dt>
+
+<dt>Compression, relation to power developed, <a href="#Page_122">122</a></dt>
+
+<dt>Compressors for producers, <a href="#Page_182">182</a></dt>
+
+<dt>Connecting-rod bearings, <a href="#Page_45">45</a></dt>
+
+<dt>Connecting-rod bearings, rational design of, <a href="#Page_45">45</a></dt>
+
+<dt>Connecting-rod, lubrication of, <a href="#Page_113">113</a>, <a href="#Page_115">115</a></dt>
+
+<dt>Consulting engineer, advisability of retaining, <a href="#Page_282">282</a></dt>
+
+<dt>Consumption at half load and full load, <a href="#Page_62">62</a></dt>
+
+<dt>Consumption at various loads, <a href="#Page_62">62</a></dt>
+
+<dt>Consumption in double or triple acting engines, <a href="#Page_62">62</a></dt>
+
+<dt>Consumption of gas, <a href="#Page_173">173</a></dt>
+
+<dt>Consumption of gas in burner, <a href="#Page_30">30</a></dt>
+
+<dt>Consumption of suction-producers, <a href="#Page_200">200</a></dt>
+
+<dt>Consumption per effective horse-power, <a href="#Page_62">62</a></dt>
+
+<dt>Cooler for gas, <a href="#Page_199">199</a></dt>
+
+<dt>Cooler, for producer, <a href="#Page_240">240</a></dt>
+
+<dt>Coolers, <a href="#Page_107">107</a></dt>
+
+<dt>Coolers, size of, <a href="#Page_109">109</a></dt>
+
+<dt>Cooling of cylinder, <a href="#Page_98">98</a>, <a href="#Page_100">100</a>, <a href="#Page_156">156</a></dt>
+
+<dt>Cooling of producer-gas engines, <a href="#Page_203">203</a></dt>
+
+<dt>Cooling, thermo-siphon, <a href="#Page_100">100</a></dt>
+
+<dt>Cost of oil and volatile hydrocarbon engines, <a href="#Page_268">268</a></dt>
+
+<dt>Crank-pin, tensile strength of, <a href="#Page_51">51</a></dt>
+
+<dt>Crank-shaft, <a href="#Page_50">50</a>, <a href="#Page_51">51</a></dt>
+
+<dt>Crank-shaft bearings, <a href="#Page_44">44</a></dt>
+
+<dt>Crank-shaft bearings, design of, <a href="#Page_46">46</a></dt>
+
+<dt>Crank-shaft, effect of premature explosion on, <a href="#Page_30">30</a></dt>
+
+<dt>Crank-shaft lubrication, <a href="#Page_117">117</a></dt>
+
+<dt>Crank-shaft, material of, <a href="#Page_50">50</a></dt>
+
+<dt>Crosshead, care of, <a href="#Page_123">123</a></dt>
+
+<dt>Cycle, analysis of, <a href="#Page_276">276</a></dt>
+
+<dt>Cylinder, arrangement of, <a href="#Page_41">41</a></dt>
+
+<dt>Cylinder, cleaning of, <a href="#Page_122">122</a></dt>
+
+<dt>Cylinder, cooling of, <a href="#Page_156">156</a></dt>
+
+<dt>Cylinder, evacuation of, <a href="#Page_83">83</a>, <a href="#Page_131">131</a></dt>
+
+<dt>Cylinder, gravel in, <a href="#Page_137">137</a></dt>
+
+<dt>Cylinder, grinding of, <a href="#Page_42">42</a></dt>
+
+<dt>Cylinder, incandescent particles in, <a href="#Page_142">142</a></dt>
+
+<dt>Cylinder, independence of casing, Compression in, <a href="#Page_42">42</a></dt>
+
+<dt>Cylinder-jacket (see Water-jacket)</dt>
+
+<dt>Cylinder lubrication, <a href="#Page_112">112</a></dt>
+
+<dt>Cylinder-oil, <a href="#Page_112">112</a>, <a href="#Page_149">149</a></dt>
+
+<dt>Cylinder, overhang in horizontal engines, <a href="#Page_42">42</a></dt>
+
+<dt>Cylinder, overheating of, <a href="#Page_148">148</a></dt>
+
+<dt>Cylinder, presence of water in, <a href="#Page_136">136</a></dt>
+
+<dt>Cylinder-shell, <a href="#Page_41">41</a></dt>
+
+<dt>Cylinder, smoke from, <a href="#Page_149">149</a></dt>
+
+<dt>Cylinder, temperature during operation of engine, <a href="#Page_132">132</a></dt>
+
+<dt>Cylinder, thrust of, <a href="#Page_43">43</a></dt>
+
+<dt>Cylinder, tightness of, <a href="#Page_122">122</a>
+
+<!--307.png--><span class='pagenum'>307</span></dt>
+
+<dt class="indexsubhdr">D</dt>
+
+<dt>Damper, Pintsch, <a href="#Page_224">224</a></dt>
+
+<dt>Dampers, <a href="#Page_223">223</a></dt>
+
+<dt>Detonations, untimely, <a href="#Page_141">141</a></dt>
+
+<dt>Distributing mechanism, derangement of, <a href="#Page_152">152</a></dt>
+
+<dt>Drain-cock in gas-pipes, <a href="#Page_70">70</a>, <a href="#Page_75">75</a></dt>
+
+<dt>Drain-cocks, testing of, <a href="#Page_256">256</a></dt>
+
+<dt>Drier for producer-gas, <a href="#Page_248">248</a></dt>
+
+<dt>Dust-collector, <a href="#Page_239">239</a></dt>
+
+<dt>Dust-collector, Benz, <a href="#Page_239">239</a></dt>
+
+<dt>Dust-collector, Bollinckx, <a href="#Page_239">239</a></dt>
+
+<dt>Dust-collector, Pintsch, <a href="#Page_239">239</a></dt>
+
+<dt>Dust-collector, Wiedenfeld, <a href="#Page_239">239</a></dt>
+
+<dt>Dynamo, lifting brushes from, in stopping engine, <a href="#Page_132">132</a></dt>
+
+<dt class="indexsubhdr">E</dt>
+
+<dt>Ebelmen principle, <a href="#Page_195">195</a></dt>
+
+<dt>Engine, Banki, <a href="#Page_264">264</a></dt>
+
+<dt>Engine, Diesel, <a href="#Page_264">264</a></dt>
+
+<dt>Engine, producer-gas and steam, compared, <a href="#Page_203">203</a></dt>
+
+<dt>Engine, selection of, <a href="#Page_279">279</a></dt>
+
+<dt>Engine, starting a producer-gas, <a href="#Page_258">258</a></dt>
+
+<dt>Engineer, duty of a consulting, <a href="#Page_281">281</a></dt>
+
+<dt>Engines, governing oil, <a href="#Page_265">265</a></dt>
+
+<dt>Engines, oil, <a href="#Page_264">264</a>, <a href="#Page_265">265</a></dt>
+
+<dt>Engines, producer-gas, <a href="#Page_153">153</a></dt>
+
+<dt>Engines, producer-gas, temperature of, <a href="#Page_157">157</a></dt>
+
+<dt>Engines, specifications of, <a href="#Page_281">281</a></dt>
+
+<dt>Engines, speed of oil, <a href="#Page_264">264</a></dt>
+
+<dt>Engines, tests of, <a href="#Page_268">268</a></dt>
+
+<dt>Engines, volatile hydrocarbon, <a href="#Page_264">264</a>, <a href="#Page_267">267</a></dt>
+
+<dt>Engines, writers on oil, <a href="#Page_266">266</a></dt>
+
+<dt>Escape-pipes, <a href="#Page_228">228</a></dt>
+
+<dt>Essences, <a href="#Page_264">264</a></dt>
+
+<dt>Exhaust, <a href="#Page_83">83</a></dt>
+
+<dt>Exhaust, back pressure to, <a href="#Page_151">151</a></dt>
+
+<dt>Exhaust, determination of resistance to, <a href="#Page_274">274</a></dt>
+
+<dt>Exhaust into sewer or chimney, <a href="#Page_85">85</a></dt>
+
+<dt>Exhaust, noises of, <a href="#Page_94">94</a>, <a href="#Page_141">141</a></dt>
+
+<dt>Exhaust period, <a href="#Page_22">22</a></dt>
+
+<dt>Exhaust, water in, <a href="#Page_136">136</a></dt>
+
+<dt>Exhausters, <a href="#Page_183">183</a></dt>
+
+<dt>Exhaust-chest, <a href="#Page_83">83</a></dt>
+
+<dt>Exhaust-muffler, <a href="#Page_86">86</a>, <a href="#Page_94">94</a></dt>
+
+<dt>Exhaust-pipe, <a href="#Page_83">83</a>, <a href="#Page_85">85</a></dt>
+
+<dt>Exhaust-pipe, design of, <a href="#Page_96">96</a>, <a href="#Page_97">97</a></dt>
+
+<dt>Exhaust-pipe, joints for, <a href="#Page_85">85</a></dt>
+
+<dt>Exhaust-pipe, oil in, <a href="#Page_151">151</a></dt>
+
+<dt>Exhaust-valve, binding of, <a href="#Page_152">152</a></dt>
+
+<dt>Exhaust-valve, cooling of, <a href="#Page_25">25</a></dt>
+
+<dt>Expansion-boxes, <a href="#Page_95">95</a></dt>
+
+<dt>Expansion period, <a href="#Page_22">22</a></dt>
+
+<dt>Expert, necessity of an, <a href="#Page_282">282</a>, <a href="#Page_283">283</a></dt>
+
+<dt>Explosion, spontaneous, <a href="#Page_140">140</a></dt>
+
+<dt>Explosion-engines (see Gas-engines)</dt>
+
+<dt>Explosion period, <a href="#Page_22">22</a></dt>
+
+<dt>Explosion-recorder, analysis of inertia of, <a href="#Page_277">277</a></dt>
+
+<dt>Explosion-recorder for industrial engines, <a href="#Page_285">285</a></dt>
+
+<dt>Explosion-recorder, the continuous, <a href="#Page_269">269</a></dt>
+
+<dt>Explosions, comparison of average force of, <a href="#Page_275">275</a></dt>
+
+<dt>Explosion-records, <a href="#Page_288">288</a></dt>
+
+<dt>Explosions, retarded, <a href="#Page_143">143</a></dt>
+
+<dt class="indexsubhdr">F</dt>
+
+<dt>Fans for producers, <a href="#Page_181">181</a></dt>
+
+<dt>Feeder, Winterthur, <a href="#Page_236">236</a></dt>
+
+<dt>Feed-hopper, <a href="#Page_224">224</a></dt>
+
+<dt>Fire-box, door of, <a href="#Page_221">221</a></dt>
+
+<dt>Flues, escape, <a href="#Page_228">228</a></dt>
+
+<dt>Fly-wheel, oil on, <a href="#Page_120">120</a></dt>
+
+<dt>Fly-wheel, starting the, <a href="#Page_131">131</a></dt>
+
+<dt>Fly-wheels, <a href="#Page_46">46</a></dt>
+
+<dt>Fly-wheels as pulleys, <a href="#Page_46">46</a></dt>
+
+<dt>Fly-wheels, balancing of, <a href="#Page_46">46</a></dt>
+
+<dt>Fly-wheels, curved spoke, how mounted, <a href="#Page_49">49</a></dt>
+
+<dt>Fly-wheels, fastening of, <a href="#Page_46">46</a></dt>
+
+<dt>Fly-wheels, proper mounting of, <a href="#Page_46">46</a></dt>
+
+<dt>Fly-wheels, rim of, <a href="#Page_46">46</a></dt>
+
+<dt>Fly-wheels, single, <a href="#Page_48">48</a>, <a href="#Page_92">92</a></dt>
+
+<dt>Fly-wheels, single, for dynamo-engines, <a href="#Page_46">46</a></dt>
+
+<dt>Fly-wheels, straight and curved spoke, <a href="#Page_49">49</a></dt>
+
+<dt>Fly-wheels with hit-and-miss system, <a href="#Page_50">50</a></dt>
+
+<dt>Foundation, <a href="#Page_44">44</a>, <a href="#Page_87">87</a></dt>
+
+<dt>Foundation, design of, <a href="#Page_88">88</a>, <a href="#Page_89">89</a></dt>
+
+<dt>Foundation, excavation for, <a href="#Page_88">88</a></dt>
+
+<dt>Foundation, insulation of, <a href="#Page_89">89</a>, <a href="#Page_90">90</a></dt>
+
+<dt>Foundation of dynamo-engine, <a href="#Page_91">91</a>
+
+<!--308.png--><span class='pagenum'>308</span></dt>
+
+<dt>Frame, <a href="#Page_43">43</a></dt>
+
+<dt>Frame, method of securing, to foundation, <a href="#Page_44">44</a></dt>
+
+<dt>Fuel of producers, <a href="#Page_178">178</a>, <a href="#Page_187">187</a>, <a href="#Page_254">254</a></dt>
+
+<dt>Fuel, qualities of, <a href="#Page_201">201</a></dt>
+
+<dt>Fuel (see also Lignite, Peat, Sawdust, Wood, Coal, etc.)</dt>
+
+<dt>Fuel, size of, <a href="#Page_201">201</a></dt>
+
+<dt>Fuel, smoke-producing, <a href="#Page_254">254</a></dt>
+
+<dt class="indexsubhdr">G</dt>
+
+<dt>Gas, ascertaining purity of, <a href="#Page_128">128</a></dt>
+
+<dt>Gas, blast-furnace, <a href="#Page_153">153</a></dt>
+
+<dt>Gas, calorific value of, <a href="#Page_284">284</a></dt>
+
+<dt>Gas, calorific value of producer, <a href="#Page_200">200</a></dt>
+
+<dt>Gas, coke-oven, <a href="#Page_153">153</a></dt>
+
+<dt>Gas consumption, <a href="#Page_173">173</a></dt>
+
+<dt>Gas consumption of burner, <a href="#Page_30">30</a></dt>
+
+<dt>Gas, effect of quality, <a href="#Page_152">152</a></dt>
+
+<dt>Gas-engine, balancing of, <a href="#Page_46">46</a></dt>
+
+<dt>Gas-engine, care during operation, <a href="#Page_131">131</a></dt>
+
+<dt>Gas-engine, cost of installation, <a href="#Page_19">19</a></dt>
+
+<dt>Gas-engine, cost of operation, <a href="#Page_19">19</a></dt>
+
+<dt>Gas-engine, difficulties in starting, <a href="#Page_134">134</a></dt>
+
+<dt>Gas-engine, how to start a, <a href="#Page_128">128</a></dt>
+
+<dt>Gas-engine, how to stop a, <a href="#Page_132">132</a></dt>
+
+<dt>Gas-engine, installation of a, <a href="#Page_68">68</a></dt>
+
+<dt>Gas-engine, location of a, <a href="#Page_68">68</a></dt>
+
+<dt>Gas-engine, selection of a, <a href="#Page_21">21</a></dt>
+
+<dt>Gas-engine, simplicity of installation, <a href="#Page_17">17</a></dt>
+
+<dt>Gas-engine, the four-cycle, <a href="#Page_21">21</a></dt>
+
+<dt>Gas-engines, adjustment of, <a href="#Page_126">126</a></dt>
+
+<dt>Gas-engines, care of, <a href="#Page_121">121</a></dt>
+
+<dt>Gas-engines, "Steam-Hammer," <a href="#Page_57">57</a></dt>
+
+<dt>Gas-engines, temperature of, <a href="#Page_158">158</a></dt>
+
+<dt>Gas-engines, tests of, <a href="#Page_283">283</a></dt>
+
+<dt>Gas-engines, vertical, <a href="#Page_56">56</a></dt>
+
+<dt>Gas-engines, writers on, <a href="#Page_68">68</a></dt>
+
+<dt>Gas, fuel, <a href="#Page_153">153</a></dt>
+
+<dt>Gas-holder, <a href="#Page_186">186</a>, <a href="#Page_189">189</a></dt>
+
+<dt>Gas-holders, <a href="#Page_247">247</a></dt>
+
+<dt>Gas-holder, combined with washer or scrubber, <a href="#Page_186">186</a></dt>
+
+<dt>Gas, illuminating (see Street-gas)</dt>
+
+<dt>Gas, impurities of, <a href="#Page_172">172</a></dt>
+
+<dt>Gas, Mond, <a href="#Page_153">153</a>, <a href="#Page_167">167</a></dt>
+
+<dt>Gasometer (see Gas-holder)</dt>
+
+<dt>Gas, producer (see Producer-gas)</dt>
+
+<dt>Gas production, <a href="#Page_173">173</a></dt>
+
+<dt>Gas, purification of wood, <a href="#Page_195">195</a></dt>
+
+<dt>Gas supply, necessity of coolness, <a href="#Page_69">69</a></dt>
+
+<dt>Gas-valve, necessity of independent operation of, <a href="#Page_27">27</a></dt>
+
+<dt>Gas, water, <a href="#Page_153">153</a>, <a href="#Page_169">169</a></dt>
+
+<dt>Gas, wood, <a href="#Page_153">153</a>, <a href="#Page_168">168</a></dt>
+
+<dt>Gases, analysis of, <a href="#Page_290">290</a></dt>
+
+<dt>Generator (see also Producer)</dt>
+
+<dt>Generator, Benz, <a href="#Page_207">207</a></dt>
+
+<dt>Generator, Bollinckx, <a href="#Page_207">207</a></dt>
+
+<dt>Generator, care of, <a href="#Page_259">259</a></dt>
+
+<dt>Generator, charging the, <a href="#Page_259">259</a></dt>
+
+<dt>Generator, construction of, <a href="#Page_177">177</a>, <a href="#Page_207">207</a></dt>
+
+<dt>Generator, dimensions of, <a href="#Page_252">252</a></dt>
+
+<dt>Generator, Dowson, <a href="#Page_177">177</a></dt>
+
+<dt>Generator, firing the, <a href="#Page_205">205</a>, <a href="#Page_256">256</a></dt>
+
+<dt>Generator, hot operation of, <a href="#Page_252">252</a></dt>
+
+<dt>Generator of suction producer, <a href="#Page_205">205</a></dt>
+
+<dt>Generator, operation of, <a href="#Page_251">251</a></dt>
+
+<dt>Generator, Pierson, <a href="#Page_215">215</a></dt>
+
+<dt>Generator, Pintsch, <a href="#Page_207">207</a></dt>
+
+<dt>Generator, Taylor, <a href="#Page_207">207</a></dt>
+
+<dt>Generator, Wiedenfeld, <a href="#Page_207">207</a></dt>
+
+<dt>Generator, Winterthur, <a href="#Page_207">207</a></dt>
+
+<dt>Generator with internal vaporizer, <a href="#Page_206">206</a></dt>
+
+<dt>Generators, blowing, <a href="#Page_169">169</a></dt>
+
+<dt>Generators, pressure, <a href="#Page_169">169</a>, <a href="#Page_177">177</a></dt>
+
+<dt>Governor, ball, <a href="#Page_52">52</a>, <a href="#Page_53">53</a></dt>
+
+<dt>Governor, care during operation, <a href="#Page_131">131</a></dt>
+
+<dt>Governor, hit-and-miss, <a href="#Page_52">52</a>, <a href="#Page_54">54</a></dt>
+
+<dt>Governor, inertia, <a href="#Page_53">53</a></dt>
+
+<dt>Governor, sensitiveness of, <a href="#Page_52">52</a></dt>
+
+<dt>Governors, <a href="#Page_53">53</a></dt>
+
+<dt>Governors, adjustment of, <a href="#Page_124">124</a></dt>
+
+<dt>Governors, care of, <a href="#Page_123">123</a></dt>
+
+<dt>Governors, centrifugal, <a href="#Page_56">56</a></dt>
+
+<dt>Governors, centrifugal, with hit-and-miss regulation, <a href="#Page_55">55</a></dt>
+
+<dt>Governors for oil-engines, <a href="#Page_265">265</a></dt>
+
+<dt>Governors for producer-gas engines, <a href="#Page_161">161</a></dt>
+
+<dt>Governors, hit-and-miss, <a href="#Page_54">54</a></dt>
+
+<dt>Governors, variable admission, <a href="#Page_56">56</a></dt>
+
+<dt>Grate, B&eacute;nier's, <a href="#Page_216">216</a></dt>
+
+<dt>Grate of generator-lining, <a href="#Page_214">214</a></dt>
+
+<dt>Grate, Kiderlen, <a href="#Page_216">216</a></dt>
+
+<dt>Grate, Pintsch, <a href="#Page_216">216</a></dt>
+
+<dt>Grate, Wiedenfeld, <a href="#Page_216">216</a>
+
+<!--309.png--><span class='pagenum'>309</span></dt>
+
+<dt class="indexsubhdr">H</dt>
+
+<dt>Heater, air, <a href="#Page_238">238</a></dt>
+
+<dt>Hit-and-miss regulation (see Governors)</dt>
+
+<dt>Holders, gas, <a href="#Page_247">247</a></dt>
+
+<dt>Hopper, Bollinckx, <a href="#Page_225">225</a></dt>
+
+<dt>Hopper, Deutz, <a href="#Page_225">225</a></dt>
+
+<dt>Hopper for generator, <a href="#Page_224">224</a></dt>
+
+<dt>Hopper, removable feed, <a href="#Page_225">225</a></dt>
+
+<dt>Hopper, Taylor, <a href="#Page_225">225</a></dt>
+
+<dt>Hopper, Wiedenfeld, <a href="#Page_225">225</a></dt>
+
+<dt>Hopper, Winterthur, <a href="#Page_225">225</a></dt>
+
+<dt>Horse-power, definition of, <a href="#Page_60">60</a></dt>
+
+<dt>Horse-power, determination of, <a href="#Page_61">61</a></dt>
+
+<dt>Horse-power (see also Power)</dt>
+
+<dt>Hot tubes (see Tubes)</dt>
+
+<dt>Hydrocarbons, volatile, for engine fuel, <a href="#Page_264">264</a></dt>
+
+<dt class="indexsubhdr">I</dt>
+
+<dt>Ignition, <a href="#Page_27">27</a>, <a href="#Page_122">122</a></dt>
+
+<dt>Ignition, adjustment of, <a href="#Page_144">144</a></dt>
+
+<dt>Ignition by battery and coil, <a href="#Page_31">31</a></dt>
+
+<dt>Ignition by magneto, <a href="#Page_33">33</a></dt>
+
+<dt>Ignition, curing defects of electric, <a href="#Page_145">145</a></dt>
+
+<dt>Ignition, defective, <a href="#Page_152">152</a></dt>
+
+<dt>Ignition, disadvantages of belated, <a href="#Page_28">28</a></dt>
+
+<dt>Ignition, disadvantages of premature, <a href="#Page_28">28</a></dt>
+
+<dt>Ignition, effect of lost motion, <a href="#Page_146">146</a></dt>
+
+<dt>Ignition, effect of mixture composition on, <a href="#Page_28">28</a></dt>
+
+<dt>Ignition, effect of temperature of flame on, <a href="#Page_28">28</a></dt>
+
+<dt>Ignition, effect of water on, <a href="#Page_136">136</a></dt>
+
+<dt>Ignition, electric, <a href="#Page_30">30</a>, <a href="#Page_139">139</a></dt>
+
+<dt>Ignition, electric, regulation of, <a href="#Page_145">145</a></dt>
+
+<dt>Ignition, faulty, <a href="#Page_143">143</a></dt>
+
+<dt>Ignition for high-pressure engines, <a href="#Page_35">35</a></dt>
+
+<dt>Ignition, hot-tube, <a href="#Page_159">159</a></dt>
+
+<dt>Ignition, imperfect, <a href="#Page_137">137</a></dt>
+
+<dt>Ignition, objections to electric, <a href="#Page_31">31</a></dt>
+
+<dt>Ignition of producer-gas, <a href="#Page_160">160</a></dt>
+
+<dt>Ignition, premature, <a href="#Page_139">139</a>, <a href="#Page_142">142</a></dt>
+
+<dt>Ignition, premature, in high-pressure engines, <a href="#Page_158">158</a></dt>
+
+<dt>Ignition, prevention of, by faulty compression, <a href="#Page_134">134</a></dt>
+
+<dt>Ignition, proper timing of, <a href="#Page_27">27</a></dt>
+
+<dt>Ignition, spontaneous, <a href="#Page_140">140</a>, <a href="#Page_159">159</a></dt>
+
+<dt>Ignition, tests prior to starting engine, <a href="#Page_129">129</a></dt>
+
+<dt>Ignition-tubes (see Tubes)</dt>
+
+<dt>Incrustation of water-jacket, <a href="#Page_98">98</a>, <a href="#Page_148">148</a></dt>
+
+<dt>Incrustation, prevention of, <a href="#Page_107">107</a></dt>
+
+<dt>Incrustations, <a href="#Page_255">255</a></dt>
+
+<dt>Indicators, <a href="#Page_285">285</a></dt>
+
+<dt>Indicator-records, <a href="#Page_127">127</a></dt>
+
+<dt>Induction-coil, <a href="#Page_32">32</a></dt>
+
+<dt>Installation, laws governing gas-engine, <a href="#Page_86">86</a></dt>
+
+<dt class="indexsubhdr">J</dt>
+
+<dt>Joints, <a href="#Page_125">125</a></dt>
+
+<dt>Joints, care of, <a href="#Page_124">124</a></dt>
+
+<dt class="indexsubhdr">L</dt>
+
+<dt>Laming mass, <a href="#Page_246">246</a></dt>
+
+<dt>Laws governing gas-engines, <a href="#Page_86">86</a></dt>
+
+<dt>Leakage of pipes, <a href="#Page_69">69</a></dt>
+
+<dt>Lift-valve for charging-box, <a href="#Page_223">223</a></dt>
+
+<dt>Lignite in producers, <a href="#Page_188">188</a></dt>
+
+<dt>Lining, refractory, <a href="#Page_211">211</a></dt>
+
+<dt>Lining, support for generator, <a href="#Page_214">214</a></dt>
+
+<dt>Loads, consumption at half and full, <a href="#Page_62">62</a></dt>
+
+<dt>Location of engine, <a href="#Page_68">68</a></dt>
+
+<dt>Lubricate (see Oils)</dt>
+
+<dt>Lubricating-pumps, <a href="#Page_115">115</a></dt>
+
+<dt>Lubrication, <a href="#Page_111">111</a>, <a href="#Page_121">121</a></dt>
+
+<dt>Lubrication, difficulties entailed by, <a href="#Page_119">119</a></dt>
+
+<dt>Lubrication, faulty, <a href="#Page_149">149</a></dt>
+
+<dt>Lubrication of crank-shaft, <a href="#Page_117">117</a></dt>
+
+<dt>Lubrication of high-power engine, <a href="#Page_116">116</a></dt>
+
+<dt>Lubrication of valve-stem, <a href="#Page_119">119</a></dt>
+
+<dt>Lubricator, cotton-waste, <a href="#Page_117">117</a></dt>
+
+<dt>Lubricators, automatic, <a href="#Page_113">113</a></dt>
+
+<dt>Lubricators, disconnection of, when stopping engine, <a href="#Page_132">132</a></dt>
+
+<dt>Lubricators, examination of, before starting, <a href="#Page_129">129</a></dt>
+
+<dt>Lubricators, feed of, <a href="#Page_121">121</a></dt>
+
+<dt>Lubricators, revolving-ring, <a href="#Page_118">118</a></dt>
+
+<dt>Lubricators, sight-feed, <a href="#Page_118">118</a></dt>
+
+<dt>Lubricators, types of, <a href="#Page_113">113</a>
+
+<!--310.png--><span class='pagenum'>310</span></dt>
+
+<dt class="indexsubhdr">M</dt>
+
+<dt>Magneto, adaptability for producer-gas, <a href="#Page_35">35</a></dt>
+
+<dt>Magneto, control of, <a href="#Page_35">38</a></dt>
+
+<dt>Magneto, efficiency of, <a href="#Page_34">34</a></dt>
+
+<dt>Magneto-igniter, construction of, <a href="#Page_35">35</a></dt>
+
+<dt>Magneto ignition, <a href="#Page_33">33</a></dt>
+
+<dt>Magneto ignition, precautions to be taken, <a href="#Page_34">34</a></dt>
+
+<dt>Magneto, inspection of, before starting engine, <a href="#Page_139">129</a></dt>
+
+<dt>Magneto, mechanical control of, <a href="#Page_33">33</a></dt>
+
+<dt>Magneto, operation of, <a href="#Page_33">33</a></dt>
+
+<dt>Magneto, regulation of, <a href="#Page_37">37</a></dt>
+
+<dt>Maintenance of plants, <a href="#Page_295">295</a></dt>
+
+<dt>Manograph, <a href="#Page_269">269</a></dt>
+
+<dt>Mass, Laming, <a href="#Page_246">246</a></dt>
+
+<dt>Meters, capacity of, <a href="#Page_70">70</a></dt>
+
+<dt>Meters, dry, <a href="#Page_72">72</a></dt>
+
+<dt>Meters, evaporation in wet, <a href="#Page_70">70</a></dt>
+
+<dt>Meters, falsification of records, <a href="#Page_70">70</a></dt>
+
+<dt>Meters, inclination of, <a href="#Page_71">71</a></dt>
+
+<dt>Meters, size of, <a href="#Page_71">71</a></dt>
+
+<dt>Misfire, <a href="#Page_137">137</a></dt>
+
+<dt>Mixture, effect of high compression in, <a href="#Page_155">155</a></dt>
+
+<dt>Mixture, effect of high pressure on, <a href="#Page_156">156</a></dt>
+
+<dt>Mixture, governing by varying the, <a href="#Page_161">161</a>-164</dt>
+
+<dt>Mixture, poorness of, <a href="#Page_143">143</a></dt>
+
+<dt>Mixture, pressure of, <a href="#Page_26">26</a></dt>
+
+<dt>Mixture-valve, necessity of independence of operation of, <a href="#Page_27">27</a></dt>
+
+<dt>Mortar for foundation, <a href="#Page_87">87</a></dt>
+
+<dt>Motion, lost, <a href="#Page_146">146</a></dt>
+
+<dt>Muffler for exhaust, <a href="#Page_86">86</a>, <a href="#Page_94">94</a></dt>
+
+<dt class="indexsubhdr">N</dt>
+
+<dt>Naphthalene in gas-pipes, <a href="#Page_70">70</a></dt>
+
+<dt>Noises, cause of, <a href="#Page_92">92</a></dt>
+
+<dt>Noises of exhaust, <a href="#Page_94">94</a></dt>
+
+<dt class="indexsubhdr">O</dt>
+
+<dt>Oilers (see Lubricators)</dt>
+
+<dt>Oiling (see Lubrication)</dt>
+
+<dt>Oil, addition of sulphur to, <a href="#Page_147">147</a></dt>
+
+<dt>Oil, cylinder, <a href="#Page_149">149</a></dt>
+
+<dt>Oil-engines, <a href="#Page_264">264</a>, <a href="#Page_265">265</a></dt>
+
+<dt>Oil-engines, governing, <a href="#Page_265">265</a></dt>
+
+<dt>Oil-engines, speed of, <a href="#Page_264">264</a></dt>
+
+<dt>Oil-engines, writers on, <a href="#Page_266">266</a></dt>
+
+<dt>Oil for engine fuel, <a href="#Page_264">264</a></dt>
+
+<dt>Oil, freezing of, <a href="#Page_150">150</a></dt>
+
+<dt>Oil-guard for fly-wheel, <a href="#Page_120">120</a></dt>
+
+<dt>Oil-lamp, <a href="#Page_266">266</a></dt>
+
+<dt>Oil, prevention of spreading on fly-wheel, <a href="#Page_120">120</a></dt>
+
+<dt>Oil-pumps, <a href="#Page_115">115</a>, <a href="#Page_226">226</a></dt>
+
+<dt>Oil, quality of, <a href="#Page_150">150</a></dt>
+
+<dt>Oil, splashing of, <a href="#Page_119">119</a></dt>
+
+<dt>Oil-tank, <a href="#Page_266">266</a></dt>
+
+<dt>Oils, how tested, <a href="#Page_112">112</a></dt>
+
+<dt>Oils, mineral for lubrication, <a href="#Page_112">112</a></dt>
+
+<dt>Oils, purification of, <a href="#Page_113">113</a></dt>
+
+<dt>Oils, quality of, <a href="#Page_112">112</a></dt>
+
+<dt>Oils, requisites of, <a href="#Page_112">112</a></dt>
+
+<dt>Operation, steadiness of, <a href="#Page_52">52</a></dt>
+
+<dt>Otto cycle, <a href="#Page_21">21</a></dt>
+
+<dt>Overheating, <a href="#Page_152">152</a></dt>
+
+<dt>Overheating, prevention of, <a href="#Page_147">147</a></dt>
+
+<dt class="indexsubhdr">P</dt>
+
+<dt>Pacini treatment, <a href="#Page_171">171</a></dt>
+
+<dt>Peat in producers, <a href="#Page_188">188</a></dt>
+
+<dt>Perturbations, <a href="#Page_134">134</a></dt>
+
+<dt>Petrol (see Oil)</dt>
+
+<dt>Pipe-hangers, <a href="#Page_86">86</a></dt>
+
+<dt>Pipes, <a href="#Page_69">69</a></dt>
+
+<dt>Pipes, cross-section of, <a href="#Page_70">70</a></dt>
+
+<dt>Pipes, disposition of, <a href="#Page_77">77</a></dt>
+
+<dt>Pipes, escape, <a href="#Page_228">228</a></dt>
+
+<dt>Pipes, exposure to cold, <a href="#Page_69">69</a></dt>
+
+<dt>Pipes for exhaust, <a href="#Page_83">83</a></dt>
+
+<dt>Pipes for producer-gas, <a href="#Page_249">249</a></dt>
+
+<dt>Pipes for water-tanks, <a href="#Page_102">102</a>, <a href="#Page_103">103</a>, <a href="#Page_105">105</a></dt>
+
+<dt>Pipes, hanging of, <a href="#Page_86">86</a></dt>
+
+<dt>Pipes, insulation from foundations and walls, <a href="#Page_94">94</a></dt>
+
+<dt>Pipes, leakage of, <a href="#Page_69">69</a></dt>
+
+<dt>Pipes, minimum diameter of branch, <a href="#Page_81">81</a></dt>
+
+<dt>Pipes, proper size of, <a href="#Page_70">70</a></dt>
+
+<dt>Piston, <a href="#Page_39">39</a>, <a href="#Page_122">122</a></dt>
+
+<dt>Piston, avoidance of insertions or projections, <a href="#Page_39">39</a></dt>
+
+<dt>Piston, cleaning of, <a href="#Page_141">141</a></dt>
+
+<dt>Piston, curved faces inadvisable, <a href="#Page_39">39</a></dt>
+
+<dt>Piston, direct connection with crank-shaft, <a href="#Page_43">43</a>
+
+<!--311.png--><span class='pagenum'>311</span></dt>
+
+<dt>Piston, finish of, <a href="#Page_41">41</a></dt>
+
+<dt>Piston, importance of, <a href="#Page_111">111</a></dt>
+
+<dt>Piston, leakage of, <a href="#Page_136">136</a></dt>
+
+<dt>Piston, overheating of, <a href="#Page_148">148</a></dt>
+
+<dt>Piston, position of, in starting, <a href="#Page_130">130</a></dt>
+
+<dt>Piston, rear face of, <a href="#Page_39">39</a></dt>
+
+<dt>Piston-pin, construction of bearing at, <a href="#Page_40">40</a></dt>
+
+<dt>Piston-pin, location of, <a href="#Page_41">41</a></dt>
+
+<dt>Piston-pin, locking of, <a href="#Page_40">40</a></dt>
+
+<dt>Piston-pin, lubrication of, <a href="#Page_113">113</a></dt>
+
+<dt>Piston-pin, material of, <a href="#Page_40">40,</a> <a href="#Page_51">51</a></dt>
+
+<dt>Piston-pin, strength of, <a href="#Page_40">40</a></dt>
+
+<dt>Piston-rings, fouling of, <a href="#Page_149">149</a></dt>
+
+<dt>Piston-rings, material of, <a href="#Page_41">41</a></dt>
+
+<dt>Piston-rings, number of, <a href="#Page_41">41</a></dt>
+
+<dt>Piston-rod, effect of premature explosion on, <a href="#Page_30">30</a></dt>
+
+<dt>Piston-wear, <a href="#Page_40">40</a></dt>
+
+<dt>Poisoning, carbon monoxide, <a href="#Page_170">170</a></dt>
+
+<dt>Porcelain of spark-plug, <a href="#Page_32">32</a></dt>
+
+<dt>Power, definition of, <a href="#Page_60">60</a></dt>
+
+<dt>Power, measuring engine, <a href="#Page_285">285</a></dt>
+
+<dt>Power, "Nominal," <a href="#Page_61">61</a></dt>
+
+<dt>Precautions to be taken in starting, <a href="#Page_128">128</a></dt>
+
+<dt>Pressure, back, to exhaust, <a href="#Page_151">151</a></dt>
+
+<dt>Pressure-generators, <a href="#Page_169">169</a>, <a href="#Page_177">177</a></dt>
+
+<dt>Pressure in producer-gas engines, <a href="#Page_160">160</a></dt>
+
+<dt>Pressure-lubricators, <a href="#Page_114">114</a></dt>
+
+<dt>Pressure-producers, <a href="#Page_174">174</a></dt>
+
+<dt>Pressure-regulator, bell as, <a href="#Page_187">187</a></dt>
+
+<dt>Pressure-regulators, <a href="#Page_77">77</a></dt>
+
+<dt>Pressure-regulators, their construction, <a href="#Page_78">78</a></dt>
+
+<dt>Pressures, high, in producer-gas engines, <a href="#Page_154">154</a></dt>
+
+<dt>Preheaters, <a href="#Page_229">229</a></dt>
+
+<dt>Producer, assembling, <a href="#Page_253">253</a></dt>
+
+<dt>Producer, B&eacute;nier, <a href="#Page_216">216</a></dt>
+
+<dt>Producer, Benz, <a href="#Page_220">228</a>, <a href="#Page_239">239</a>, <a href="#Page_240">240</a></dt>
+
+<dt>Producer, Bollinckx, <a href="#Page_206">206</a>, <a href="#Page_220">220</a>, <a href="#Page_225">225</a>, <a href="#Page_228">228</a>, <a href="#Page_234">234</a>, <a href="#Page_239">239</a></dt>
+
+<dt>Producer, Chavanon, <a href="#Page_229">229</a></dt>
+
+<dt>Producer, cleaning of, <a href="#Page_261">261</a></dt>
+
+<dt>Producer, Dawson, <a href="#Page_174">174</a></dt>
+
+<dt>Producer, Deschamps, <a href="#Page_198">198</a></dt>
+
+<dt>Producer, Deutz, <a href="#Page_206">206</a>, <a href="#Page_220">220</a>, <a href="#Page_224">224</a>, <a href="#Page_225">225</a>, <a href="#Page_228">228</a>, <a href="#Page_229">229</a>, <a href="#Page_240">240</a></dt>
+
+<dt>Producer, Deutz, <a href="#Page_231">231</a>, <a href="#Page_232">232</a></dt>
+
+<dt>Producer, Deutz lignite, <a href="#Page_188">188</a></dt>
+
+<dt>Producer, Duff, <a href="#Page_195">195</a></dt>
+
+<dt>Producer, Fang&eacute;-Chavanon, <a href="#Page_198">198</a></dt>
+
+<dt>Producer, Fichet-Heurty, <a href="#Page_240">240</a>, <a href="#Page_245">245</a></dt>
+
+<dt>Producer, Gardie, <a href="#Page_183">183</a></dt>
+
+<dt>Producer-gas, <a href="#Page_153">153</a></dt>
+
+<dt>Producer-gas, <a href="#Page_165">165</a></dt>
+
+<dt>Producer-gas as a furnace fuel, <a href="#Page_177">177</a></dt>
+
+<dt>Producer-gas, calorific value of, <a href="#Page_200">200</a></dt>
+
+<dt>Producer-gas, composition of, <a href="#Page_166">166</a></dt>
+
+<dt>Producer-gas plants, tests of, <a href="#Page_297">297</a></dt>
+
+<dt>Producer-gas, writers on, <a href="#Page_154">154</a></dt>
+
+<dt>Producer, general arrangement of suction, <a href="#Page_204">204</a></dt>
+
+<dt>Producer, Goebels, <a href="#Page_206">206</a></dt>
+
+<dt>Producer, Hille, <a href="#Page_206">206</a>, <a href="#Page_239">239</a></dt>
+
+<dt>Producer, Kiderlen, <a href="#Page_206">206</a></dt>
+
+<dt>Producer, Kiderlen, <a href="#Page_216">216</a></dt>
+
+<dt>Producer, Koerting, <a href="#Page_232">232</a></dt>
+
+<dt>Producer, Lencauchez, <a href="#Page_212">212</a>, <a href="#Page_214">214</a></dt>
+
+<dt>Producer, Ph&#339;nix, <a href="#Page_217">217</a></dt>
+
+<dt>Producer, Pierson, <a href="#Page_224">224</a>, <a href="#Page_229">229</a></dt>
+
+<dt>Producer, Pintsch, <a href="#Page_206">206</a>, <a href="#Page_216">216</a>, <a href="#Page_224">224</a>, <a href="#Page_231">231</a>, <a href="#Page_232">232</a>, <a href="#Page_239">239</a>, <a href="#Page_245">245</a>, <a href="#Page_248">248</a></dt>
+
+<dt>Producer, Rich&eacute;, <a href="#Page_168">168</a>, <a href="#Page_190">190</a>, <a href="#Page_193">193</a>, <a href="#Page_195">195</a>, <a href="#Page_216">216</a></dt>
+
+<dt>Producer (see also Generator)</dt>
+
+<dt>Producer, stoppage of, <a href="#Page_261">261</a></dt>
+
+<dt>Producer, Taylor, <a href="#Page_206">206</a>, <a href="#Page_214">214</a>, <a href="#Page_225">225</a>, <a href="#Page_231">231</a>, <a href="#Page_232">232</a></dt>
+
+<dt>Producer, test by smoke, <a href="#Page_254">254</a></dt>
+
+<dt>Producer, test of Deutz, <a href="#Page_298">298</a></dt>
+
+<dt>Producer, test of Dowson, <a href="#Page_296">296</a></dt>
+
+<dt>Producer, tests of Winterthur, <a href="#Page_297">297</a></dt>
+
+<dt>Producer, Thwaite, <a href="#Page_195">195</a></dt>
+
+<dt>Producer, Wiedenfeld, <a href="#Page_206">206</a>, <a href="#Page_216">216</a>, <a href="#Page_220">220</a>, <a href="#Page_225">225</a>, <a href="#Page_234">234</a>, <a href="#Page_239">239</a></dt>
+
+<dt>Producer, Winterthur, <a href="#Page_225">225</a>, <a href="#Page_228">228</a>, <a href="#Page_236">236</a></dt>
+
+<dt>Producers, advantages of suction, <a href="#Page_195">199</a></dt>
+
+<dt>Producers, combustion, <a href="#Page_193">193</a></dt>
+
+<dt>Producers, conditions of perfect operation, <a href="#Page_251">251</a></dt>
+
+<dt>Producers, consumption of suction, <a href="#Page_200">200</a></dt>
+
+<dt>Producers, distilling, <a href="#Page_190">190</a></dt>
+
+<dt>Producers, efficiency of, <a href="#Page_201">201</a></dt>
+
+<dt>Producers, efficiency of lignite, <a href="#Page_190">190</a></dt>
+
+<dt>Producers, efficiency of wood, <a href="#Page_194">194</a></dt>
+
+<dt>Producers, lignite, <a href="#Page_188">188</a></dt>
+
+<dt>Producers, maintenance of, <a href="#Page_254">254</a></dt>
+
+<dt>Producers, peat, <a href="#Page_188">188</a></dt>
+
+<dt>Producers, pressure, <a href="#Page_174">174</a></dt>
+
+<dt>Producers, self-reducing, <a href="#Page_193">193</a></dt>
+
+<dt>Producers, specifications of, <a href="#Page_281">281</a>
+
+<!--312.png--><span class='pagenum'>312</span></dt>
+
+<dt>Producers, suction, <a href="#Page_199">199</a></dt>
+
+<dt>Producers, suction (see also Suction-producers)</dt>
+
+<dt>Producers, tests of, <a href="#Page_297">297</a></dt>
+
+<dt>Producers with external vaporizers, <a href="#Page_206">206</a></dt>
+
+<dt>Production of gas, <a href="#Page_173">173</a></dt>
+
+<dt>Pulley, disconnection of, in stopping engine, <a href="#Page_132">132</a></dt>
+
+<dt>Pump, circulating with by-pass, <a href="#Page_105">106</a></dt>
+
+<dt>Purifier, fiber, <a href="#Page_185">185</a></dt>
+
+<dt>Purifier, Fichet-Heurtey, <a href="#Page_245">245</a></dt>
+
+<dt>Purifier, material for, <a href="#Page_245">245</a></dt>
+
+<dt>Purifier, moss, <a href="#Page_185">185</a></dt>
+
+<dt>Purifier, Pintsch, <a href="#Page_245">245</a></dt>
+
+<dt>Purifier, sawdust, <a href="#Page_185">185</a></dt>
+
+<dt>Purifiers for gas, <a href="#Page_184">184</a></dt>
+
+<dt>Purifiers for producer-gas, <a href="#Page_244">244</a></dt>
+
+<dt class="indexsubhdr">R</dt>
+
+<dt>Recorder, analysis of inertia of explosion, <a href="#Page_277">277</a></dt>
+
+<dt>Recorder, explosion, for industrial engines, <a href="#Page_285">285</a></dt>
+
+<dt>Recorder, the continuous explosion, <a href="#Page_269">269</a></dt>
+
+<dt>Records of engines, <a href="#Page_284">284</a></dt>
+
+<dt>Records of explosions, <a href="#Page_288">288</a></dt>
+
+<dt>Records, indicator, <a href="#Page_127">127</a></dt>
+
+<dt>Regrinding of valves, <a href="#Page_122">122</a></dt>
+
+<dt>Regularity, cyclic, <a href="#Page_48">48</a>, <a href="#Page_53">53</a></dt>
+
+<dt>Remagnetization of magnetos, <a href="#Page_33">33</a></dt>
+
+<dt>Resuscitation after asphyxiation, <a href="#Page_171">171</a></dt>
+
+<dt>Retort, cleaning of, <a href="#Page_225">225</a></dt>
+
+<dt>Retort of producer, <a href="#Page_190">190</a></dt>
+
+<dt>Retort, support, <a href="#Page_214">214</a></dt>
+
+<dt>Revolutions, variations in number of, <a href="#Page_52">52</a></dt>
+
+<dt>Rollers, <a href="#Page_51">51</a></dt>
+
+<dt>Running, steadiness of, <a href="#Page_52">52</a></dt>
+
+<dt class="indexsubhdr">S</dt>
+
+<dt>Sand for foundation, <a href="#Page_87">87</a></dt>
+
+<dt>Sawdust in producers, <a href="#Page_193">193</a></dt>
+
+<dt>Scavenging, <a href="#Page_142">142</a>, <a href="#Page_155">155</a></dt>
+
+<dt>Scrubber, <a href="#Page_189">189</a>, <a href="#Page_199">199</a></dt>
+
+<dt>Scrubber, combined with gas-holder, <a href="#Page_186">186</a></dt>
+
+<dt>Scrubber for producer-gas, <a href="#Page_240">240</a></dt>
+
+<dt>Scrubber, size of, <a href="#Page_253">253</a></dt>
+
+<dt>Selection of gas-engine, <a href="#Page_21">21</a></dt>
+
+<dt>Shavings in producers, <a href="#Page_193">193</a></dt>
+
+<dt>Slide-valve for charging-box, <a href="#Page_223">223</a></dt>
+
+<dt>Slide-valve, its disadvantages, <a href="#Page_23">23</a></dt>
+
+<dt>Sluice-valves, <a href="#Page_101">101</a></dt>
+
+<dt>Smoke from cylinder, <a href="#Page_149">149</a></dt>
+
+<dt>Spark-plug, <a href="#Page_32">32</a></dt>
+
+<dt>Specifications of engines, <a href="#Page_281">281</a></dt>
+
+<dt>Specifications of producers, <a href="#Page_281">281</a></dt>
+
+<dt>Speed, how to increase, <a href="#Page_124">124</a></dt>
+
+<dt>Speed of oil-engines, <a href="#Page_264">264</a></dt>
+
+<dt>Speed of volatile hydrocarbon engines, <a href="#Page_264">264</a></dt>
+
+<dt>Speed, variation of, with load, <a href="#Page_52">52</a></dt>
+
+<dt>Spokes of fly-wheels, <a href="#Page_49">49</a></dt>
+
+<dt>Spring for valves (see Valves)</dt>
+
+<dt>Springs, selection of, for explosion-recorder, <a href="#Page_277">277</a></dt>
+
+<dt>Starter, Tangye, <a href="#Page_65">65</a></dt>
+
+<dt>Starting an engine, <a href="#Page_128">128</a></dt>
+
+<dt>Starting, automatic, <a href="#Page_63">63</a>, <a href="#Page_130">130</a></dt>
+
+<dt>Starting by compressed air, <a href="#Page_64">64</a></dt>
+
+<dt>Starting by hand, <a href="#Page_63">63</a></dt>
+
+<dt>Starting by hand-pumps, <a href="#Page_64">64</a></dt>
+
+<dt>Starting, difficulties in, <a href="#Page_134">134</a></dt>
+
+<dt>Starting, how accomplished, <a href="#Page_66">66</a></dt>
+
+<dt>Starting of producer-gas engine, <a href="#Page_258">258</a></dt>
+
+<dt>Steadiness, <a href="#Page_52">52</a></dt>
+
+<dt>Steam-engine, cost of installation, <a href="#Page_19">19</a></dt>
+
+<dt>Steam-engine, cost of operation, <a href="#Page_19">19</a></dt>
+
+<dt>Stoppage of producer, <a href="#Page_261">261</a></dt>
+
+<dt>Stopping the engine, <a href="#Page_132">132</a></dt>
+
+<dt>Stops, sudden, <a href="#Page_151">151</a></dt>
+
+<dt>Straw in producers, <a href="#Page_193">193</a>, <a href="#Page_254">254</a></dt>
+
+<dt>Street-gas, <a href="#Page_165">165</a></dt>
+
+<dt>Suction, determination of resistance to, <a href="#Page_274">274</a></dt>
+
+<dt>Suction, noises caused by, <a href="#Page_141">141</a></dt>
+
+<dt>Suction of air, <a href="#Page_81">81</a></dt>
+
+<dt>Suction period, <a href="#Page_21">21</a></dt>
+
+<dt>Suction-producer, general arrangement of, <a href="#Page_204">204</a></dt>
+
+<dt>Suction-producers, <a href="#Page_199">199</a></dt>
+
+<dt>Suction-producers, advantages of, <a href="#Page_199">199</a></dt>
+
+<dt>Suction-producers, efficiency of, <a href="#Page_201">201</a></dt>
+
+<dt>Suction-valve, leakage of, <a href="#Page_142">142</a></dt>
+
+<dt>Super-heater, Winterthur, <a href="#Page_236">236</a></dt>
+
+<dt>Sylvester treatment, <a href="#Page_171">171</a></dt>
+
+<dt class="indexsubhdr">T</dt>
+
+<dt>Tanks, connection of, <a href="#Page_105">105</a>
+
+<!--313.png--><span class='pagenum'>313</span></dt>
+
+<dt>Tanks, design of, <a href="#Page_103">103</a></dt>
+
+<dt>Tanks, location of, <a href="#Page_102">102</a></dt>
+
+<dt>Tanks for water-jacket, how mounted, <a href="#Page_101">101</a></dt>
+
+<dt>Tar in producer-plants, <a href="#Page_200">200</a></dt>
+
+<dt>Tar, removal of, <a href="#Page_250">250</a></dt>
+
+<dt>Tar (see also Scrubber, Purifier, etc.)</dt>
+
+<dt>Taylor, A., <a href="#Page_199">199</a></dt>
+
+<dt>Terminals of magneto apparatus, <a href="#Page_34">34</a></dt>
+
+<dt>Tests of gas-engine plants, <a href="#Page_283">283</a></dt>
+
+<dt>Tests of high-speed engines, <a href="#Page_268">268</a></dt>
+
+<dt>Tests of producer-gas engines, <a href="#Page_297">297</a></dt>
+
+<dt>Thrust-bearings, <a href="#Page_51">51</a></dt>
+
+<dt>Tongue, traction of, in asphyxiation cases, <a href="#Page_172">172</a></dt>
+
+<dt>Tower, washer, <a href="#Page_244">244</a></dt>
+
+<dt>Town-gas (see Street-gas)</dt>
+
+<dt>Tree branches for coolers, <a href="#Page_107">107</a></dt>
+
+<dt>Trepidations, <a href="#Page_92">92</a></dt>
+
+<dt>Tube, gas-supply pipe of incandescent, <a href="#Page_77">77</a></dt>
+
+<dt>Tube, incandescent, <a href="#Page_27">27</a></dt>
+
+<dt>Tube, incandescent, adjustment of, <a href="#Page_144">144</a></dt>
+
+<dt>Tube, incandescent, breakage of, <a href="#Page_137">137</a></dt>
+
+<dt>Tube, incandescent, danger of breaking, <a href="#Page_131">131</a></dt>
+
+<dt>Tube, incandescent, how started, <a href="#Page_128">128</a></dt>
+
+<dt>Tube, incandescent, leakage of, <a href="#Page_138">138</a></dt>
+
+<dt>Tubes as vaporizers, <a href="#Page_231">231</a></dt>
+
+<dt>Tubes, incandescent, <a href="#Page_28">28</a>, <a href="#Page_159">159</a></dt>
+
+<dt>Tubes, incandescent, valved, <a href="#Page_29">29</a></dt>
+
+<dt>Tubes, use of special valves with incandescent, <a href="#Page_29">29</a></dt>
+
+<dt>Tubes, valveless ignition, <a href="#Page_28">28</a></dt>
+
+<dt class="indexsubhdr">V</dt>
+
+<dt>Valve-chests, <a href="#Page_124">124</a></dt>
+
+<dt>Valve mechanism, slide, <a href="#Page_23">23</a></dt>
+
+<dt>Valve-regrinding, <a href="#Page_122">122</a>, <a href="#Page_135">135</a></dt>
+
+<dt>Valve-stem lubrication, <a href="#Page_119">119</a></dt>
+
+<dt>Valves, <a href="#Page_122">122</a></dt>
+
+<dt>Valves, accessibility of, <a href="#Page_25">25</a></dt>
+
+<dt>Valves, cooling of, <a href="#Page_25">25</a></dt>
+
+<dt>Valves, cooling of, in high-pressure engines, <a href="#Page_156">156</a></dt>
+
+<dt>Valves, defective operation of, <a href="#Page_135">135</a></dt>
+
+<dt>Valves, free, <a href="#Page_27">27</a></dt>
+
+<dt>Valves, mechanical control of, <a href="#Page_27">27</a></dt>
+
+<dt>Valves, modern, <a href="#Page_24">24</a></dt>
+
+<dt>Valves, necessity of cleanliness, <a href="#Page_25">25</a></dt>
+
+<dt>Valves, regulation of, before starting, <a href="#Page_129">129</a></dt>
+
+<dt>Valves, requisites of, <a href="#Page_25">25</a></dt>
+
+<dt>Valves, retardation in action of, <a href="#Page_146">146</a></dt>
+
+<dt>Vaporizer, Bollinckx, <a href="#Page_234">234</a></dt>
+
+<dt>Vaporizer, Chavanon, <a href="#Page_229">229</a>, <a href="#Page_234">234</a></dt>
+
+<dt>Vaporizer, Deutz, <a href="#Page_231">231</a>, <a href="#Page_232">232</a>, <a href="#Page_229">229</a>, <a href="#Page_225">225</a></dt>
+
+<dt>Vaporizer, Field, <a href="#Page_233">233</a></dt>
+
+<dt>Vaporizer, internal, <a href="#Page_206">206</a></dt>
+
+<dt>Vaporizer, Koerting, <a href="#Page_232">232</a></dt>
+
+<dt>Vaporizer, maintenance of, <a href="#Page_255">255</a></dt>
+
+<dt>Vaporizer, operation of, <a href="#Page_234">234</a></dt>
+
+<dt>Vaporizer, Pierson, <a href="#Page_229">229</a></dt>
+
+<dt>Vaporizer, Pintsch, <a href="#Page_231">231</a>, <a href="#Page_232">232</a></dt>
+
+<dt>Vaporizer-preheaters, <a href="#Page_229">229</a></dt>
+
+<dt>Vaporizer, size of, <a href="#Page_253">253</a></dt>
+
+<dt>Vaporizer, Taylor, <a href="#Page_231">231</a>, <a href="#Page_232">232</a></dt>
+
+<dt>Vaporizer, Wiedenfeld, <a href="#Page_225">225</a>, <a href="#Page_234">234</a></dt>
+
+<dt>Vaporizers, external, <a href="#Page_206">206</a>, <a href="#Page_230">230</a></dt>
+
+<dt>Vaporizers, internal, <a href="#Page_229">229</a></dt>
+
+<dt>Vaporizers, partition, <a href="#Page_234">234</a></dt>
+
+<dt>Vaporizers, regulation of, <a href="#Page_236">236</a></dt>
+
+<dt>Vaporizers, tubular, <a href="#Page_231">231</a></dt>
+
+<dt>Ventilation in engine-room, <a href="#Page_69">69</a></dt>
+
+<dt>Vibration, <a href="#Page_89">89</a></dt>
+
+<dt>Vibration of air, <a href="#Page_92">92</a></dt>
+
+<dt>Vibration, prevention of, <a href="#Page_89">89</a>, <a href="#Page_90">90</a></dt>
+
+<dt class="indexsubhdr">W</dt>
+
+<dt>Water circulation, <a href="#Page_98">98</a>, <a href="#Page_107">107</a>, <a href="#Page_125">125</a></dt>
+
+<dt>Water circulation by pump, <a href="#Page_107">107</a></dt>
+
+<dt>Water circulation, care during operation, <a href="#Page_132">132</a></dt>
+
+<dt>Water circulation, how effected, <a href="#Page_102">102</a></dt>
+
+<dt>Water circulation, prevention of freezing, <a href="#Page_133">133</a></dt>
+
+<dt>Water-coolers, <a href="#Page_106">106</a></dt>
+
+<dt>Water-coolers, size of, <a href="#Page_109">109</a></dt>
+
+<dt>Water for circulation, <a href="#Page_99">99</a></dt>
+
+<dt>Water for producer-gas engines, <a href="#Page_203">203</a></dt>
+
+<dt>Water-gas, <a href="#Page_153">153</a>, <a href="#Page_167">167</a></dt>
+
+<dt>Water in cylinder, <a href="#Page_136">136</a></dt>
+
+<dt>Water in exhaust, <a href="#Page_136">136</a></dt>
+
+<dt>Water-jacket, <a href="#Page_41">41</a>, <a href="#Page_98">98</a>, <a href="#Page_125">125</a>, <a href="#Page_157">157</a></dt>
+
+<dt>Water-jacket, incrustation of, <a href="#Page_148">148</a></dt>
+
+<dt>Water-jacket, outlet of, <a href="#Page_98">98</a></dt>
+
+<dt>Water-jacket, prevention of incrustation, <a href="#Page_107">107</a></dt>
+
+<dt>Water-pipe, <a href="#Page_102">102</a>
+
+<!--314.png--><span class='pagenum'>314</span></dt>
+
+<dt>Water, purification of, for circulation, <a href="#Page_98">98</a></dt>
+
+<dt>Water, running, for jacket, <a href="#Page_98">98</a></dt>
+
+<dt>Water-tanks, <a href="#Page_101">101</a></dt>
+
+<dt>Water-tanks, connection of, <a href="#Page_103">103</a>, <a href="#Page_105">105</a></dt>
+
+<dt>Water-tanks, design of, <a href="#Page_103">103</a></dt>
+
+<dt>Water-tanks, location of, <a href="#Page_102">102</a></dt>
+
+<dt>Washer, Benz, <a href="#Page_240">240</a></dt>
+
+<dt>Washer, combined with gas-holder, <a href="#Page_186">186</a></dt>
+
+<dt>Washer, Deutz, <a href="#Page_240">240</a></dt>
+
+<dt>Washer, Fichet-Heurtey, <a href="#Page_240">240</a></dt>
+
+<dt>Washer for gas, <a href="#Page_199">199</a></dt>
+
+<dt>Washer for producer-gas, <a href="#Page_240">240</a></dt>
+
+<dt>Washer, maintenance of, <a href="#Page_256">256</a></dt>
+
+<dt>Washer, material employed in, <a href="#Page_242">242</a></dt>
+
+<dt>Washer, Winterthur, <a href="#Page_240">240</a></dt>
+
+<dt>Washers, <a href="#Page_184">184</a></dt>
+
+<dt>Wear, premature, <a href="#Page_146">146</a></dt>
+
+<dt>Witz apparatus, <a href="#Page_284">284</a></dt>
+
+<dt>Wood as fuel, <a href="#Page_254">254</a></dt>
+
+<dt>Wood, calorific value, <a href="#Page_194">194</a></dt>
+
+<dt>Wood-gas, <a href="#Page_153">153</a>, <a href="#Page_168">168</a></dt>
+
+<dt>Wood-gas, purification of, <a href="#Page_195">195</a></dt>
+
+<dt>Wood in producers, <a href="#Page_190">190</a>, <a href="#Page_192">192</a>, <a href="#Page_193">193</a></dt>
+
+<dt>Work, definition of effective, <a href="#Page_60">60</a></dt>
+</dl>
+
+<hr class="ChapterTopRule" />
+<!--315.png-->
+<div class="center">ADVERTISEMENTS</div>
+
+<div class="ads">
+  <div class="c3">THE MIETZ &amp; WEISS</div>
+  <div class="c1"><span class="smcap">Oil Engine</span></div>
+  <table border="0" cellpadding="4" cellspacing="0" summary="Mietz-Weiss engines.">
+  <tr>
+    <td align='center' style="width: 35%">STATIONARY<br />1 to 75 H.P.</td>
+    <td>&nbsp;</td>
+    <td align='center' style="width: 35%">MARINE<br />1 to 60 H.P.</td>
+  </tr>
+  </table>
+  <div class="figcenter" style="width: 500px;">
+  <img src="images/fig_315.jpg" width="500" height="301" alt="50 H.P. GENERATOR SET." title="" />
+  </div>
+  <div class="c4">50 H.P. GENERATOR SET</div>
+  <div class="c3">KEROSENE OR FUEL OIL</div>
+  <hr style='width: 15%;' />
+  <div class="c3">Air Compressors, Generator Sets,
+  Hoisting Engines</div>
+  <hr style='width: 15%;' />
+  <div class="c4">Centrifugal and Triplex Pumps and Engines
+  Direct Coupled</div>
+  <div class="hangingindent">Medal of Excellence&mdash;American Institute, 1897.</div>
+  <div class="hangingindent">Highest Award for Direct Oil Engine, Generator Set&mdash;Paris Universal
+  Exposition, 1900.</div>
+  <div class="hangingindent">Gold Medal&mdash;Pan-American Exposition, 1901.</div>
+  <div class="hangingindent">Gold Medal&mdash;Charleston Exposition, 1902.</div>
+  <div class="hangingindent">Gold Medal&mdash;Louisiana Purchase Exposition, 1904.</div>
+  <div class="c3">A. MIETZ</div>
+  <table width="100%" summary="Address."><tr><td>87-89 Elizabeth St.</td><td class="right">128-138 Mott St., New York</td></tr></table>
+</div>
+
+<hr style="width: 95%;" />
+<!--316.png-->
+
+<div class="ads">
+  <div class="c2">SPLITDORF JUMP-SPARK</div>
+  <div class="c4">IGNITION APPARATUS</div>
+  <table summary="Splitdorf ignition apparatus.">
+    <tr><td>Constructed to give Good Satisfaction Permanently</td>
+    <td><div class="figcenter" style="width: 400px;">
+    <img src="images/fig_316.jpg" width="400" height="240" alt="SPLITDORF JUMP SPARK IGNITION APPARATUS." title="" />
+    </div></td>
+    <td>The only Real Standard High Tension Apparatus</td></tr>
+  </table>
+  <span style="float: left; font-size: 1.5em;">F. SPLITDORF</span>
+    <span style="float: right">17-27 Vandswater Street,<br />New York, N.Y.</span>
+
+  <hr style="width: 65%;" />
+
+  <div class="figcenter" style="width: 500px;">
+  <img src="images/fig_316a.jpg" width="500" height="202" alt="Gas Producers by DR. OSKAR NAGEL." title="" />
+  </div>
+
+  <div class="c3">CHEAPEST POWER SUCTION</div>
+  <div class="c1">Gas Producers</div>
+  <div class="c3">DR. OSKAR NAGEL</div>
+
+  <table width="100%" summary="Address."><tr><td>90 Wall Street</td><td class="right">NEW YORK</td></tr></table>
+
+  <hr style="width: 65%;" />
+
+  <table width="600" border="0" cellpadding="10" cellspacing="0" summary="E.H. Kellogg">
+    <tr>
+      <td style="font-size: 2em;" class="center" colspan="2">E.H. KELLOGG &amp; CO.</td>
+      <td class="center">Established<br />1858</td>
+    </tr>
+    <tr>
+      <td class="figcenter" style="width: 200px;">
+      <img src="images/fig_316b.jpg" width="200" height="211" alt="E.H. KELLOGG." title="E.H. KELLOGG" /></td>
+      <td class="center">Sole Manufacturers of the<br />
+        World Renowned<br />
+        <span style="font-size: 2.5em">OILS</span><br />
+        <span style="font-size: 1.4em">Best Grades Lubricants<br /></span>
+        <span style="font-size: 1em">Railway, Dynamo,<br />
+          Gas Engine, Ice Machine, Steamship</span>
+      </td>
+      <td class="figcenter" style="width: 200px;">
+          <img src="images/fig_316c.jpg" width="200" height="202" alt="E.H. KELLOGG." title="x" /></td>
+    </tr>
+    <tr>
+      <td colspan="1" style="font-size: 0.7em">New York, Liverpool, London, Bremen,<br />
+          Hamburg, Bombay, Calcutta.
+      </td>
+      <td colspan="2" class="right">243 &amp; 244 South St., New York, U.S.A.
+      </td>
+    </tr>
+  </table>
+</div>
+
+<hr style="width: 95%;" />
+<!--317.png-->
+
+<div class="ads">
+  <table border="0" cellpadding="4" cellspacing="0" style="width:100%;" summary="suction">
+    <tr>
+      <td colspan="2" style="font-size: 2em; text-indent: -4em; padding-left: 4.5em">
+        Suction Gas Producers<br />and Backus Gas Engines
+      </td>
+    </tr>
+    <tr>
+      <td style="font-size: 1.2em" class="center">One Horse Power</td>
+      <td class="center">With 1<sup>1</sup>&frasl;<sub>4</sub> lbs. Pea Coal<br />per Hour</td>
+    </tr>
+    <tr>
+      <td colspan="2"><span class="figcenter" style="width: 600px; margin-top: 0;">
+        <img src="images/fig_317.jpg" width="600" height="323" alt="Engine illustration." title="" /></span>
+      </td>
+    </tr>
+    <tr>
+      <td colspan="2" style="font-size: 1.3em; padding-top: 1em; text-align: center;">
+          BACKUS WATER MOTOR CO.</td>
+    </tr>
+    <tr>
+      <td colspan="2" style="font-size: 1.1em; text-align: right; padding-right: 3em; padding-bottom: 1em;">
+          Newark, N.J., U.S.A.</td>
+    </tr>
+  </table>
+</div>
+
+<div class="ads">
+  <table border="0" cellpadding="8" cellspacing="0"
+         style="text-align: center;" summary="Scientific American Books">
+    <tr><td style="font-size: 2em; text-align: left;">We Will Send</td></tr>
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+    <tr><td>Our complete catalogue of scientific and practical
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+      and all practical men.</td></tr>
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+<!--318.png-->
+
+<div style="width: 600px; border-color: black; border-style: double; border-width: .4em; padding: 2em;">
+
+  <div class="c1">THE GAS ENGINE</div>
+  <div class="c1">MAGAZINE</div>
+  <span style="float: left; font-weight: bold;">Monthly</span>
+    <span style="float: right; font-weight: bold;">Established 1898</span>
+  <hr style="width: 100%;" />
+  <p>Devoted exclusively to the gas engine industry:
+  stationary, marine, automobile.</p>
+
+  <p>Special articles each month relative to the design,
+  construction, and operation of gas engines for all
+  classes of service.</p>
+
+  <p>New books, patents, trade items, etc., covered in
+  special articles. An expert answers subscribers'
+  inquiries free of charge.</p>
+
+  <p>Specimen copy free.</p>
+
+  <p>Subscription, $1.00 per year; foreign, $1.50.</p>
+  <hr style="width: 100%;" />
+  <div class="c3">SOME BOOKS WE PUBLISH</div>
+
+  <p><b>THE GAS ENGINE HANDBOOK</b>, by <span class="smcap">E.W.
+  Roberts</span>, M.E. Contains complete formulas for
+  gas engine design. 256 pages. Limp leather, $1.50.</p>
+
+  <p><b>THE AUTOMOBILE POCKETBOOK</b>, by <span class="smcap">E.W.
+  Roberts</span>, M.E. A book for the designer and user
+  of gasoline automobiles. 325 pages. Limp leather, $1.50.</p>
+
+  <p><b>GAS ENGINE TROUBLES AND REMEDIES</b>,
+  by <span class="smcap">Albert Stritmatter</span>. How to care for and
+  operate gas and gasoline engines. 120 pages. Cloth, $1.00.</p>
+
+  <p><b>SUCTION GAS</b>, by <span class="smcap">Oswald H. Haenssgen</span>. The construction
+  and operation of suction gas producers and producer gas
+      engines. 90 pages. Cloth, $1.00.</p>
+
+  <div class="c4">Send for our clubbing offers on above</div>
+  <hr style="width: 100%;" />
+
+  <div class="c2">THE GAS ENGINE PUBLISHING CO.</div>
+
+  <span style="float: left;">60 Blymyer Building </span><span style="float: right;">Cincinnati, Ohio</span>
+
+</div>
+
+<hr style="width: 95%;" />
+<!--319.png-->
+
+<div style="width: 600px; border-color: black; border-style: double; border-width: .4em; padding: 2em;">
+
+<div class="center">
+  <span style="font-size: 3em">R. E. MATHOT</span><br />
+  <span style="font-weight: bold">Consulting Engineer</span><br />
+
+  <div class="c4">FOR</div>
+
+  <div class="c3">Gas Engines and<br />
+  Gas Producer Plants</div>
+  <div class="c4" style="margin-bottom: 0;">Referee to Courts of Laeo</div>
+  <hr style="width: 35%;" />
+
+  <i>Member</i>: British Institution Mechanical Engineers.<br />
+  Soci&eacute;t&eacute; des Ing&eacute;nieurs Civils de France.<br />
+  Association des Ing&eacute;nieurs des Mines du Hainaut.<br /><br />
+  <span style="font-weight: bold">At BRUSSELS (Belgium, Europe.)<br /><br /></span>
+</div>
+
+<div class="center">Expert Opinions on Gas Power Installations.<br />
+<span style="margin-left: 5em;">Mechanical Laboratory for Testing Gas Engines.<br /></span>
+<span style="margin-left: 10em;">Chemical Analyses of Fuels.<br /></span>
+<span style="margin-left: 15em;">Scientific Investigations.<br /><br /></span>
+Plans revised and corrected for mill and factory proprietors.<br />
+Engines and power plants designed by your own engineer
+under my personal supervision.
+</div>
+
+<div class="c2">R. E. MATHOT</div>
+<span style="float: left">BRUSSELS </span><span style="float: right">BELGIUM</span>
+
+</div>
+
+<hr style="width: 95%;" />
+<!--320.png-->
+
+<div class="ads">
+  <div class="c2">SCIENTIFIC AMERICAN</div>
+  <div class="c2">REFERENCE BOOK</div>
+
+  <div class="c5">12mo, Cloth.&nbsp; &nbsp; &nbsp;  500 Pages.&nbsp; &nbsp; &nbsp;  6 Colored Plates.&nbsp; &nbsp; &nbsp;  Price, $1.50</div>
+  <hr style="width: 35%;" />
+
+  This book is intended to furnish the reader with information
+  not obtainable in any other work of reference. It is not an
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+
+<hr style="width: 95%;" />
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+<div class="ads">
+
+  <div class="c1">PATENTS</div>
+
+  <div class="c2">The Wealth of Nations</div>
+
+  <hr style="width: 100%;" />
+
+  <p style="text-align: justify; text-indent: 0;">
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+
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+  it is invaluable, as every number contains a complete list of all
+  patents and trade-marks issued weekly from the Patent Office. It
+  promotes Industry, Progress, Thrift and Intelligence in every community
+  where it circulates.</p>
+
+  <p>The <span class="smcap">Scientific American</span> should have a place in every Dwelling, Shop,
+  Office, School, or Library. Workmen, Foremen, Engineers, Superintendents,
+  Directors, Presidents, Officials, Merchants, Farmers, Teachers, Lawyers,
+  Physicians, Clergymen&mdash;People in every walk and profession in life will
+  derive satisfaction and benefit from a regular reading of the <span class="smcap">Scientific
+  American</span>.</p>
+
+  <p>If you want to know more about the paper send for "<i>Fifteen Reasons
+  Why You Should Subscribe to the Scientific American</i>," and for "<i>Five
+  Reasons Why Inventors Should Subscribe to the Scientific American</i>."
+  Fifty-two numbers make 832 large pages, equal to 3,328 ordinary magazine
+  pages, and 1,000 illustrations are published each year. Can you and your
+  friends afford to be without this up-to-date periodical which is read by
+  every class and profession? Remit $3.00 by postal order or check for a
+  year's subscription, or $1.50 for six months.
+  </p>
+
+  <div class="c4" style="text-align: right">MUNN &amp; CO., Publishers, 361 Broadway, New York City</div>
+
+  <hr style="width: 35%;" />
+  <div class="c1">SCIENTIFIC AMERICAN</div>
+  <div class="c3">SUPPLEMENT</div>
+
+  <div class="c4">Established 1876.</div>
+
+  <p>This journal is a separate publication from the <span class="smcap">Scientific American</span>,
+  and is designed to extend and amplify the work carried on by the parent
+  paper. In size and general make-up it is uniform therewith, covering
+  sixteen pages of closely printed matter, handsomely illustrated. It has no
+  advertising pages, and the entire space is given up to the scientific,
+  mechanical and engineering news of the day. It differs from the <span class="smcap">Scientific
+  American</span> in that it contains many articles that are too long to be
+  published in the older journal, or of a more technical nature.</p>
+
+  <p>The price of the <span class="smcap">Supplement</span> is $5.00 a year, but where subscribers take
+  both the <span class="smcap">Scientific American</span> and the <span class="smcap">Scientific American
+  Supplement</span> a special combined rate of $7.00 for both is made if the
+  papers are mailed to one address. Remit by postal order or check. All
+  copies of the <span class="smcap">Supplement</span> since January 1, 1876, are in print
+  and can be supplied at the uniform price of 10 cents each, thus enabling
+  readers to obtain access to a most valuable source of information on almost
+  every subject at the most moderate price. A large <i>Supplement Catalogue</i>
+  giving a list of nearly 15,000 valuable papers will be mailed free to any
+  one. Address</p>
+
+  <div class="c4" style="text-align: right">MUNN &amp; CO., Publishers, 361 Broadway, New York City</div>
+</div>
+
+<hr style="width: 95%;" />
+<!--323.png-->
+
+<div class="ads" style="border: none">
+  <div class="c2">The Scientific American Cyclopedia</div>
+  <div class="c2">of Receipts, Notes and Queries</div>
+
+  <div class="c3"><i>REVISED EDITION</i></div>
+
+  <div class="c2">15,000 Receipts. 734 Pages. Price, $5.00.</div>
+
+  <div class="c4">MAILED TO ANY PART OF THE WORLD.</div>
+
+  <div class="c3">Leather Binding as follows: Sheep, $6.00; Half Morocco, $6.50.</div>
+  <hr style="width: 35%;" />
+
+  <div class="figcenter" style="width: 200px;">
+  <img src="images/fig_323.jpg" width="200" height="288" alt="Book cover image." title="" />
+  </div>
+
+  <p style="text-align: justify; text-indent: 0;"><span class="smcap">
+  The Scientific American Cyclopedia of Receipts, Notes and Queries</span>
+  was first published in the autumn of 1891. It was well received by the
+  press, came quickly into the favor of purchasers and has had an
+  unprecedented sale. It has been used by chemists, technologists, and
+  those unfamiliar with the arts, with equal success, and has demonstrated
+  that it is a book which is useful in the laboratory, factory or home. It
+  consists of a careful compilation of the most useful receipts, and
+  information germane to the scope of the book, which have appeared in <span class="smcap">The
+  Scientific American</span> for more than half a century. The Publishers now
+  take pleasure in offering the Sixteenth Revised Edition, which has been
+  brought up to the latest requirements by the insertion of 900 new
+  formul&aelig;, making it the latest and most complete volume on the subject of
+  receipts ever presented. Over 15,000 selected formul&aelig; are here
+  collected, nearly every branch of the useful arts being represented.
+  Many of the principal substances and raw materials used in the arts are
+  described, and almost every inquiry relating to formul&aelig; will be found
+  answered. It is more than a receipt book, as in most cases it gives all
+  the standard and special formul&aelig;, thus enabling the reader to find a
+  receipt which fits his peculiar need. An alphabetical arrangement with
+  abundant cross references makes it an easy work to consult. Those who
+  are engaged in any branch of industry will find this book of the
+  greatest practical value, and we especially commend it to those who are
+  in search of an independent business, as they will find many formul&aelig; for
+  the manufacture of salable articles which will be worth many times the
+  cost of the book. The Appendix contains the very latest formul&aelig; as well
+  as 41 tables of weights and measures, and a dictionary of chemical
+  synonyms.</p>
+
+  <hr style="width: 35%;" />
+  <div class="c3"><i>SEND FOR FULL TABLE OF CONTENTS.</i></div>
+
+  <p style="text-indent: 0"><span style="float: left">MUNN &amp; CO., Publishers,</span>
+      <span style="float: right; text-align: center;">SCIENTIFIC AMERICAN OFFICE.<br />
+      361 Broadway, New York.</span></p>
+</div>
+
+<hr class="ChapterTopRule" />
+
+<h2>Transcriber's Notes</h2>
+
+<p><a name="Corrections" id="Corrections"></a>
+Blank pages have been deleted. Illustrations may
+have been moved. The following publishers' errors and inconsistencies
+were corrected as follows:</p>
+
+<ul>
+  <li>Fig. 59: "Thermo-siphon" was "Thermo-syphon".</li>
+  <li>Fig. 150: Second half split off to create <span class='smcap'>Fig. 150b.</span></li>
+  <li>Page viii: "If ignition occurs too" was "If ignition occur too"</li>
+  <li>Page 18: "smoke-stack" was "smokestack".</li>
+  <li>Page 19: Split illustrations and titled one "Fig. 1a".</li>
+  <li>Page 70: Rearranged table.</li>
+  <li>Page 83: "sawdust" was "saw-dust".</li>
+  <li>Page 83: "9 feet by 15 feet" was "9 feet by 75 feet" (math error).</li>
+  <li>Page 92: "crank-shaft" was "crankshaft".</li>
+  <li>Page 92: "fly-wheel" was "flywheel".</li>
+  <li>Page 105: "thermo-siphons" was "thermo-syphons".</li>
+  <li>Page 128: "gas-pipe" was "gaspipe".</li>
+  <li>Page 174, 200, 203(2 places): "horse-power" was "horsepower".</li>
+  <li>Page 205: "super-heater" was "superheater".</li>
+  <li>Page 220: "air-tight" was "airtight".</li>
+  <li>Page 239: "superheated" was "super-heated".</li>
+  <li>Page 255: "potash" was "postash".</li>
+  <li>Page 264: "59 degrees F." was "490 degrees F." (conversion error).</li>
+  <li>Page 269: "drum p''" was "drum p'".</li>
+  <li>Page 291: Fig. 150 has been split into two figures.</li>
+  <li>Page 297: "Stroke" was "Stoke".</li>
+  <li>Page 300: "Ziehe was "Zi he".</li>
+  <li>Page 301: "Messrs." was "Me rs.".</li>
+  <li>Page 323: "FOR" was "FOF".</li>
+  <li>Index: "Fire-box" was "Firebox".</li>
+  <li>Index: "Governors, ... hit-and-miss" was "hit-and miss".</li>
+  <li>Index: "Piston ... crank-shaft" was "crankshaft".</li>
+  <li>Advertisements: Chapter header "ADVERTISEMENTS" added.</li>
+</ul>
+
+<div><a href="#Start">Back to start of text.</a></div>
+
+
+
+
+
+
+
+
+<pre>
+
+
+
+
+
+End of the Project Gutenberg EBook of Gas-Engines and Producer-Gas Plants, by 
+R. E. Mathot
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+</body>
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