392 BOARD OF AGRICULTURE. [Pub. Doc. 



tubular wrought-iron 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 l)oilers 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 when 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 diiBcult to 

 drain, or surface water sometimes runs in so as to cause 

 much inconvenience. The modern greenhouses are so con- 

 structed that most of them can be heated by boilers stand- 

 ing 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. 



Heating Pipes. 

 The four-inch cast-iron pipe for heating greenhouses has 

 been almost entirely discarded, and in its place wrought- 

 iron water or gas pipe is used. Within the past few years 

 small pipes from one to two inches in diameter for radiating 

 surface have come into almost universal use in hot water 

 heating, with one or more flow pipes large enough to supply 

 many of the smaller radiating pipes. With the latter more 

 radiating surface is obtained, the water circulates more 

 rapidly, because the smaller the pipe the less water there is 

 to heat. The pipes now used are practically of the same 

 size as those used for steam, and the system of arrangement 

 is very similar. 



