INDEX. 363 



Comparison of hot air with h \l water, as a method of heatiug horticultural 

 buildings. — Air a bad conductoi. — Evaporating pans for supplying moisture. 



— Considered in respect to motion in the atmospnere — in respect to perma- 

 nency of heating power. — Water a better conductor. — Experiments on air and 

 water as modes of conducting heal, 171 



SECTION IV. 



HOT-WATER BOILERS AND PIPES. 



Size of boilers, and surfaces necessary to be exposed to the fire. — Adapta- 

 tion of the boiler to the apparatus. — Of the boiler and the quantity of water 

 contained. — The repulsion of heat by the metal of the boiler. — Table showing 

 the proportion the surface exposed to the fire must bear to the quantity of pipe, 176 



Causes tending to modify the proportions to be adopted. — Figures of boilers. 



— Estimated action of the fire upon the boilers. — Material for boilers, . . 179 

 Size and arrangement of hot-w^ater pipes most suitable for the purposes of 



heating. — Unequal rate of cooling in tne various sized pipes. — The ordinary 

 methods of arranging hot-water apparatus. — Advantage of taking the flue 

 through the house. — Laying down hot-water pipes. — Expansion of pipes 

 when heated. — Supply cisterns, 181 



Impediments to circulation. — Causes of circulation. — Amount of motive- 

 power. — Table showing the weight of water at different temperatures. — 

 Trifling cause renders an apparatus inefficient. — Methods of increasing the 

 motive-power. — The rapidity of circulation in proportion to the motive- 

 power 184 



Level of pipes. — Errors committed in the level of pipes. — Circulation takes 

 place first at the boiler. — Methods of making water circulate in pipes below 

 the level of the boiler, 188 



Accumulation of air in pipes. — Provision necessary for the escape of air. — 

 Want of attention to this the cause of failures. — The size of air vents. — Diffi- 

 culty of finding the proper place to place the air vents, 190 



SECTION V. 



VARIOUS METHODS OF HEATING DESCRIBED. 



Expense attending the ordinary methods of heating. — Polmaise method of 

 heating. — Its adoption in houses in this' country. — Its origin. — Means em- 

 ployed to promote it in England. — Description and figures of this method, . 192 



A method of combining hot air and hot water together. — Figured and de- 

 scribed. — Advantages of this method in the generation of heat and saving of 

 fuel, • 200 



Compound method of heating. — Seven ranges of houses heated by this 

 method. —Figure representing four houses heated by this plan. — Figure of 

 boiler and box. — Of supply cisterns. — Advantages of this mode of heating. — 

 Saving of fuel by it. — Simplicity of working, 203 



Tank methods of heating. — Methods figured and described. — Wooden and 

 metallic tanks. — The merits and properties of each. — Utility and simplicitv 

 of do., . 211 



Fertilization of the atmosphere by tanks. — Dissolving volatile gases in tanks. 

 Their use in English nurseries for growing young stock. — Their adaptation to 

 amateurs, in small pits, '. 223 



Representation of plant pits and description. — Uses of these pits. — Protec- 

 tion of plants during winter in them, 226 



Chambered vine borders. — Argument in favor of them. — Their utility 

 under certain circumstances. — Figure and description of a chambered border. 



— Evidence in favor of them, 228 



Cheap method of forming a chambered vine border. — Comparison of cost of 



it with manure. — Economy of their adoption. — Method of managing them. — 

 Coverings of borders 234 



31^ 



