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hot water are that a small amount of heat may be produced dur- 

 ing the fall or spring of the year, and heat will be secured more 

 cheaply. With the modern method of using small pipes for dis- 

 tribution and radiation, both steam and hot water heat can be 

 distributed with equal rapidity after the fire is started, but perhaps 

 steam may be carried a greater distance than hot water unless it be 

 under pressure. 



Boilers. 



The number of different kinds of both steam and hot water 

 boilers that are now in use is very great, and many of them have 

 reached great perfection, but it is difficult to prove that anyone of 

 the best of these is better than the others, and one must visit some 

 of the most successful houses and learn what are considered the best. 



A boiler to be satisfactory must have large grate area, large 

 heating surface in contact with the fire and as much water surface 

 as is possible directly over the fire, as it is here that the heat is the 

 greatest and the water will be moved the most rapidly. 



Most of the modern boilers are made in sections, so that the 

 size may be varied by the number of sections used, and if one 

 section breaks it can be replaced by a new one at but little cost. 

 Cast iron is largely used for greenhouse heaters, both for steam 

 find hot water, though for large plants the tubular boiler may be 

 the most economical for generating steam. 



When the establishment is large enough to warrant a night 

 watchman soft coal is used at a great saving in the cost of heating. 



Cleaning of Boilers. — A boiler that cannot be thoroughly cleaned 

 out, and that easily, is a very expensive one to run, as when the 

 heating surface becomes covered with soot and ashes little or no 

 heat can pass through this non-conducting mass. With the best 

 boilers we find openings in proper places so that brushes may be 

 passed over all the surface of the sections, and if cleaning is done 

 frequently a boiler will always be in the condition it was wlien first 

 put in, and most boilers work well at the first trial. 



Location of Boilers. — The cellar or pit is the favorite place for 

 locating the boilers and it has the advantages of economy of space, 

 and the flow pipes can be carried so high, even in a low house, as 

 to give the best possible circulation, but few cellars or pits are dry 

 enough to prevent the parts of the furnace from rusting, many of 

 them are difficult to drain, or surface water sometimes runs in so 

 as to cause much inconvenience. The modern greenhouses are so 

 constructed that most of them can be heated by boilers standing 

 on a level with their floors, and with proper care a boiler thus 

 located in a shed or out-building will last many years longer than 

 if put into the cellar or pit. 



