Polmaise Method of Heating Hothouses. 147 



has been written up and written down, week after week, by 

 men of all professions, trades and pursuits, from the peer 

 down to the peasant, and turned half the gardeners of Eng- 

 land into experimentalists ; and which, after all, is but an old 

 system with a new name. The cognomen which it bears, 

 in its new form, is that which I have placed at the head of 

 this paper. 



The principle upon which this so-called new method 

 works, — and even the system itself, — is not new. In fact, 

 this method of heating in various modifications, dates from an 

 earlier period than any other with which we are acquainted, 

 and is applied in a more practical and perfect form, to the 

 warming of many public and private buildings in this country. 

 The very general adoption of this method, however, does 

 not in the smallest degree, give us a warrant against its de- 

 fects. It has been satisfactorily ascertained, that air heated 

 to a temperature of three hundred degrees, becomes so de- 

 prived of its organic matter, and otherwise so changed in its 

 properties, as to be unfit for the sustenance of either animal 

 or vegetable life, in a state of healthy and vigorous develope- 

 ment, for any length of time ; and hence, it is obvious that 

 the admission of a current of highly heated air into a dwell- 

 ing room, or into a well glazed hothouse — if no means are 

 taken to restore its original properties, — must in a short time 

 become sensibly injurious to the animals and vegetables that 

 are compelled to breath it. 



The extravagant statements or rather m«s-statements, that 

 have frequently appeared in the Gardeners^ Chronicle of 

 London, respecting this mode of heating, by its editor, and 

 others under his influence, have misled many in this country, 

 who are totally ignorant of what the system in reality is, 

 and have had no opportunity of learning the arguments that 

 have been brought against it ; ushered into the world under 

 the alluring clap-trap of economy, — and lauded to the skies 

 by its promoters, for its heating power and adaptability, — 

 many have been deceived, by adopting the method called 

 Polmaise, until dearly purchased experience, — the best of all 

 teachers, — taught them the worthlessness of the system, and 



