CONTENTS. 
xi 
PAGE 
88. Sims’s patent combined cylinder engine 
at Carn Brea mine . . . . .69 
89. Remarks on the progress of the use of 
expansion . . . . . . ib. 
90. Duty of engines from 1822 to 1843 . 70 
91. Remarks on the practical effect and 
working of the improvements on the mining 
operations . . . . . .70 
92. Saving in money to the mines by the 
Cornish improvements since 1814 . . 74 
PART II. 
DESCRIPTION OF THE CORNISH PUMPING ENGINE, AND OF ITS VARIOUS PECULIARITIES, AS 
CONTRASTED WITH THE ORDINARY BOULTON AND WATT SINGLE-ACTING ENGINE. 
GENERAL DESCRIPTION OF THE PLATES. 
93. Notice of the engine from which the 
drawings are taken . . . . .76 
94. Enumeration of the contents of the 
Plates ....... ib. 
95. General remarks . . . .77 
THE ENGINE. 
96. Cylinder . . . . .78 
97. Steam jacket . . . . . ib. 
98. External non-conducting clothing . 79 
99. Casing to cylinder cover and bottom . 80 
100. Stuffing box for piston rod . . ib. 
101. Woolf’s piston rod cap . . 81 
102. Main beam . . . . .82 
103. Catch piece and blocks . . . ib. 
104. Plug rod . . . . .83 
105. Top nozzle . . . . . ib. 
106. Governor or regulating valve . . ib. 
107. Steam valve . . . .84 
108. Equilibrium valve . . . ib. 
109. Valve covers on top nozzle . . ib. 
110. Clothing to nozzle . . .85 
111. Bottom nozzle and exhaustion valve ib. 
112. The double-beat valve—its invention, 
improvement, and objects .... ib. 
113. Description of the double-beat valve 86 
114. Its advantages . . . .87 
115. Application to the governor, steam, 
equilibrium, and exhaustion valves . . ib. 
116. Cataract . . . . .88 
117. Its action and use . . . ib. 
118. Ancient cataract of Cornish origin, as 
used upon the atmospheric engine . . 89 
119. Eduction pipe . . . .90 
120. Position of the condensing cistern . ib. 
121. Condenser, injection cock, and valve 91 
122. Air pump and bucket—foot and de 
livery valves and hot well . . . . ib. 
123. Feedpump . . . . . ib. 
BOILERS AND BOILER APPARATUS. 
124. Interest attached to the Cornish ar 
rangements of boiler and furnace . .92 
125. Historical notice of the plan of heating 
the w r ater in boilers by internal vessels or tubes 
—Papin, Allen, Brindley, Smeaton, Watt, 
Trevithick . . . . . .92 
126. Dimensions of boilers shown in the 
Plates ....... 93 
127. Furnace . . . . .94 
128. Dimensions of water space, steam 
room, heating surface, &c. . . . ib. 
129. Smoke flues and boiler setting . ib. 
130. Advantages of the arrangement of the 
flues in the Cornish boiler . . .95 
131. These advantages often overlooked— 
answer to an objection brought against the 
Cornish boiler . . . . . .97 
132. Covering of ashes over boilers . 98 
133. Boilers are placed in a separate 
covered building—advantages of this practice ib. 
134. Proportions of heating surface and 
area of fire grate in the Cornish boiler . 99 
135. Mode of firing .... 101 
136. No fire-feeding or smoke-burning 
apparatus used . . . . . ib. 
137. Variation in number and size of boilers 
used—examples—cleansing . . .102 
138. Remarks on the Cornish form of 
boiler ....... 103 
139. Steam space .... 104 
140. Boiler nozzles and man-holes . . ib. 
141. Stop valves . . . . . ib. 
142. Steam pipe . . . . . ib. 
143. Safety valves . . . .105 
144. Drain pipe and valve . . . ib. 
145. Feed pipe and pump . . .106 
146. Regulation of the feed . . . ib. 
147. This regulation always managed by 
hand, in preference to self-acting apparatus— 
evils of the latter . . . . . ib. 
148. Water gauge .... 108 
149. Hosking’s water gauge . . . ib. 
150. Tubes for heating feed water, some 
times used . . . . . .109