HOT-AIR FURNACES. 101 



iron furnaces cannot be used, similar to those in our dwell- 

 ings, and it is also perfectly easy to make the hot air of these 

 furnaces saturated with moisture. So far from being dis- 

 couraged with this method of heating, I am convinced, on the 

 contrary, that it is a most economical and admirable way for 

 heating hillside houses. 



It is a, common opinion that with hot-air furnaces it will 

 always be found impossible to prevent dryness, dust and gas. 

 But, surely, we could raise a cloud of steam, if desirable, and 

 as for dust and gas, we may be as free from these as are our 

 parlors. 



It is a prevailing opinion, which is supported by writers of 

 eminence, that air coming in contact with hot iron is vitiated 

 and rendered injurious to plant-life. As a matter of fact, I 

 have seen the most luxurious growth of grape-foliage directly 

 over a stove in a vinery, which was heated solely in this way. 

 Of course, it would be desirable to have the cold air sub- 

 surface-drains of large capacity, so that the volume of air and 

 also a small addition of fresh external air would keep the 

 radiating surface of the furnace at moderate heat. I dwell 

 upon this method of heating, which, it will be seen, is a 

 different application of the Polmaise system, as peculiarly 

 suited to this form of houses where the ascent is so decided 

 that it is easy to distribute and equalize the heat in every 

 section. My experience inclines me to believe it to be an 

 excellent mode of heating, and very economical in the cost of 

 apparatus, as also in the use of coal. And yet the exact 

 adjustment of hot and cold air-drains can only be determined 

 by experiment, and it is not to be denied that hot-water pipes 

 are safest to those who cannot afford to experiment. 



Against this form of houses, the most serious objection is, 

 that it involves up and down hill work. This is an important 

 fact in the culture of small pot-plants, and where frequent 

 changes are required. In this case the extra labor required 

 would affect the advantages. But in the cultivation of per- 

 manent crops, either in sizable pots or in borders, the extra 

 labor of going up and down is vastly overbalanced by the 

 saving in labor in other directions. The objection that all 

 cultivators have not a hillside position, serves rather to 

 enhance the value of such a site, when it can be secured. 



