LIST OF ILLUSTRATIONS xv 



PAGE 



69 Malleable iron shaft coupling *. . . . 129 



70 Shaft hangers . . . . ' . . .130 



71 Open column ventilator gearing . . . 131 



72 Open column chain operated ventilator, gearing 131 



73 Closed column ventilator gearing . . . 132 



74 Chain system of operating ventilators . . 133 



75 Rack-and-pinion system of operating ventilators .133 



76 Ventilators operated by means of rods with uni- 



versal joints ....... 135 



77 Device for operating side ventilators . . . 136 



78 Compact machine for operating side ventilators 137 



79 Types of ventilator arms ... . 138 



80 Sliding shaft system for operating ventilators . 141 



81 Cucumbers growing in ground, no benches used. 143 



82 Tomatoes growing in solid raised beds . . 145 



83 Solid raised beds of hollow building tile . . 145 



84 Two types of wood benches .... 147 



85 A type of iron frame bench . . . 148 



86 Greenhouse bench of concrete .... 150 



87 Method of arranging benches in an uneven span 



house . . ..: . . . . . 153 



88 An arrangement of benches in a 30 foot house . 154 



89 Another arrangement of benches in a 30 foot 



house ........ 155 



90 A combination steam and hot water heating 



system ........ 162 



91 Under bench heating with large cast iron pipes . 165 



92 Diagram showing "down hill" and "up hill" sys- 



tems of hot water piping . .- 170 



93 A type of automatic air valve .... 171 



94 A method of piping a medium size house . . 178 



95 Diagram showing under-bench method of hot 



water piping ....... 179 



96 Gasoline engine arranged to circulate hot water 



in a greenhouse heating system . . . 180 



97 Automatic expansion tank ...... 182 



98 A type of mercury "generator" .... 185 



99 A corner coil 191 



100 A mortise coil 192 



101 Reducing valve 195 



102 A type of steam return trap .... 199 



103 A type of "vertical" or "square" sectional boiler 204 



104 End view of "square" sectional boiler showing 



fire travel 205 



105 Side view of "square" sectional boiler showing 



lire travel 206 



106 Battery of five cast iron sectional boilers . . 207 



