94 THE PRINCIPLES OF FLORICULTURE 



intense than steam heat and to resemble more nearly 

 thfe heat from the sun. The plant growth resulting 

 from hot-water heat is considered by many to be more 

 healthful and vigorous. In the early ranges, large pipes 

 were used for hot-water heating, and the circulation of 

 water was necessarily slow. Large boilers were also 

 necessary to heat the bulk of water required. With the 

 construction of larger greenhouses, there arose a demand 

 for a better method of heating, and steam came into more 

 general use. This continued the more popular for many 

 years. With recent improvements in forced circulation 

 of water, however, so that smaller pipes are used, hot- 

 water heating has again come into favor with a number 

 of large growers. 



Taft in his book on " Greenhouse Construction " writes : 

 " The following are among the claims made by advocates 

 of steam for their favorite heating system: (1) a lower 

 first cost ; (2) ability to maintain a steady temperature ; 

 (3) readiness with which the temperature can be raised 

 or lowered if desired ; (4) economy of coal consumption ; 

 (5) ease with which repairs can be made. 



" The hot-water men admit that these claims hold to a 

 large extent against hot-water in four-inch pipes, but 

 they contend that the men who make these claims have 

 made no comparison with modern, well-arranged hot- 

 water systems, and that, under proper conditions, the 

 latter system is preferable. Those who favor hot-water 

 claim for that method that at the most, only the first 

 claim of the steam men will stand, and that on the 

 other points, hot-water can make as good, if not better, 

 showing." 



Both methods have been wonderfully improved since 

 the above was written, and while it would still be diffi- 



