74 



TABLE OP TEMPERATURES FOR ORCHID HOUSES. 



Amateurs are often puzzled as to the quantity of piping to be 

 used in a house to maintain a particular temperature ; and though 

 these matters are best entrusted to horticultural builders, who will 

 give due consideration to the position, exposure, and other circum- 

 stances bearing on the point, yet a few hints may be useful as a 

 guide Many formula are given for the purpose of calculating the 

 approximate number of feet of piping necessary, but they are all 

 somewhat perplexing and occasionally misleading. The following, 

 based on a table by Mr. F. A. Fawkes, has the merit of simjlicity, 

 and it is, moreover, as nearly correct as any calculation of the kind 

 can be. The length of 4-inch piping named is that needed for each 

 1000 cubic feet of internal atmospheric contents, and the temperatures, 

 as elsewhere in these notep, are given in degrees Fahrenheit. 



Warmest house, 65 to 80. Lean-to houses, 55 ft. to 65 ft. 

 Spans, 60 ft. to 70 feet. 



Intermediate house, 60 to 75. Lean-to houses, 50 ft. to 60 ft. 

 Spans, 55 ft. to 65 f r. 



Cool house, 50 to 65. Lean-to houses, 40 ft. to 50 ft. 

 Spans, 45 ft. to 55 ft. 



These figures practically correspond with what is usually recom- 

 mended for span-roof houses of good size namely, warm house, four 

 rows of pipes in each side ; intermediate house, three rows ; and cool 

 house, two rows, and from them an idea can be gained as to what 

 extent of piping is. needed, but it is always advisable to have too 

 much than too little, as is proved in houses of all kinds, whether 

 devoted to plants or fruits. The greater the radiating surface the 

 more regular the temperature, and the less injurious it is to the plants 

 in severe weather when it may be necessary to keep the fires going 

 briskly 



