I08 GARDEN AND FARM TOPICS. 



flues. In heating by hot water it is important that the 

 work be given to some reputable firm, whose knowledge 

 is such as will enable them not only to judge what is the 

 proper capacity of the boiler for the number of pipes to 

 be used, but also how many pipes are necessary to be 

 used for the surface of glass to be heated. Men who 

 have done a large business in heating green-houses have 

 far better opportunities for knowledge in this matter than 

 the average gardener or florist ; and if those erecting 

 green-houses have not had extensive and varied practice, 

 they had better be guided by the men who make a busi- 

 ness of heating, as the want of the requisite knowledge 

 of these matters often works serioys mischief. Of course, 

 the size of the green-house or green-houses to be heated 

 must determine the capacity of the boiler wanted ; but 

 the boiler being properly apportioned to the length of 

 pipe, the following data, used in our own establishment, 

 may be useful. In our houses, which are 20 feet wide 

 and 100 feet long, when a night temperature of 70 is 

 required in the coldest weather, ten runs or rows of four- 

 inch pipe, five on each side ; when 60 are wanted, eight 

 runs of pipe, four on each side ; when 50 are wanted, 

 six runs of pipe ; and when only 35 or 40 are wanted, 

 four runs of pipe. This is for the latitude of New York 

 city, where the temperature rarely falls lower than 10 

 below zero. Latitudes north or south of New York 

 should be graded accordingly. If estimated by glass 

 surface, about one foot in length of four-inch pipe is ne- 

 cessary for every three and a half square feet of glass sur- 

 face, when the temperature is at 10 below zero, to keep 

 a temperature of 50 in the green-house. We now place 

 all our pipes under the side benches, as that enables us 

 to use the space under the middle for stowing away many 

 plants safely, which otherwise could not be done if the 



