Greenhouse Heating 



into the steam space without causing violent ebullition in the interior of 

 the boiler. The return tubular, the locomotive, the cast-iron sectional, and 

 some marine types of boilers, are used for greenhouse heating. ]Many adher- 

 ents of each type are to be found. 



Fuels 



The leading fuels that may be considered within reach of the florist 

 are : Bituminous Coal, Coke, Anthracite, and Crude Petroleum, known 

 as Fuel Oil. 



Bituminous Coal 



A good grade of bituminous coal, skillfully stoked, is probably the 

 cheapest fuel available for greenhouse heating. It has the disadvantage 

 of creating a lot of dirt and soot, which clouds the greenhouse glass and 

 reduces its efBciency to some extent where flowers are desired. 



For greenhouse heating purposes the free-burning grades of bituminous 

 coals, known as coking coals, that produce the minimum of smoke when 

 burned, are superior to the block, or hard bituminous splint coals. The 

 coals now being mined in West Virginia are, many of them, especially 

 adapted for greenhouse heating purposes, notably those known as the New 

 River (or Fire Creek vein) and the Pocahontas vein. The Kanawha River 

 coals mined from the Cedar Grove seam, the Kelly's Creek, or No. 5 seam, 

 and the Blacksburg seam, are superior coals for steam-heating purposes. 

 They are free-burning, leave but little ash and clinker, produce relatively 

 little smoke, are rich in carbon, being also comparatively free from sulphur 

 and phosphorus, the presence of which in a fuel shortens the life of the 

 boiler tubes and rapidly disintegrates the grate bars of furnaces. 



Anthracite 



Anthracite is next in economy to the free-burning West \^irginia bitu- 

 minous coals, and when it can be procured at reasonable prices is much 

 superior for florists' use on account of its cleanliness and the ease with 

 which it may be handled and fired. It is delivered in several sizes suitable 

 for steam purposes. Where a high steam pressure is carried, and a fireman 

 constantly in attendance, the smaller sizes, such as rice, buckwheat and pea, 

 are more economical than the larger sizes, known as egg and broken ; but 

 in low-pressure steam plants, and in hot-water plants, egg and broken coal 

 are more desirable. The smaller sizes give best results when the fire is 

 carried thinly, and is evenly spread over the grate, keeping a clean grate 

 and a lively draught. The larger sizes are suitable for plants where a 



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