ARTIFICIAL HEAT AND APPARATUS. 41 



To say tlie best we can of artificial heat, it is only a 

 necessary evil, but as we cannot do without using it, we 

 ought to put in practice the best and most economical 

 method that is at present known. The only advantages 

 arising from this necessity, is the raising of the tempera- 

 ture of, or drying the atmosphere in any given house 

 under care, so as to suit the particular purpose intended, 

 and so far, by adopting the latest improvements and fore- 

 casting as to what is required, we can work along with 

 comparative surety. There is no use of entering into a 

 theoretical disquisition of the relative properties of caloric, 

 nor of showing up the science of chemistry in combustion. 

 our object is to find out how we can at the least expense, 

 and with the more certainty, apply this subtle principle. 

 Suffice it then to say that there are about four ways in 

 which we can adapt it to our use, viz. : by steam, hot water, 

 brick flue, and what may be considered a modification of 

 the latter, the technical term Polmaise 



Steam is of no practical use, unless where a large ex- 

 tent of houses, all. in the immediate vicinity are to be 

 heated, neither can it be used with any certainty, unless 

 the water is kept up to the point when the steam is given 

 off in great quantity, so as to force it through the pipes, 

 and the heat along with it ; besides there is the great dis- 

 advantage of a want of bulk of heated substance, which is 

 sufficient reason why this mode should not be adopted, for 

 on the fire going down, the house immediately becomes 

 cold, and consequently without the most careful attention, 

 there is danger at almost any moment in severe weather, 

 of injury to, or the loss of a crop. 



Hot Wntcr has of late years become, and most deser 

 vedly so, the popular favorite for warming plant and fruit 

 houses. This method possesses the advantage of raising 

 the temperature without parching the air, or giving out 



