80 ON THE MERITS OF IRON AND WOOD Foil KOOl'S. 



labour, I may be allowed to bear witness, for during tbe last 

 fifteen years I have devoted the best energies of my mind to the 

 subject. Throughout that period I worked four steam boilers, 

 and had under my own eye the direction and application of no 

 less than six of the most approved systems for raising temperature 

 by means of hot water. This extensive experience and the 

 opportunities it afforded of drawing an impartial judgment on 

 the merits and defects of all the different systems, added to a 

 natural taste for, and love of experiment, directed me to the con- 

 struction of my economic egg shaped, wrought iron boiler, which 

 has not only received the direct approbation of every engineer 

 who has witnessed its operations,^but is considered by them and 

 all who have adopted it, as the most simple and economical of all 

 the plans as yet submitted to the public. So confident am I in its 

 superiority, that I always offer aguarrantee to all who employ me 

 to fix it, that I will keep it in repair and take the responsi- 

 bility of its acting properly for three years, provided that it be 

 fairly used. On such conditions, those who favour my invention 

 cannot run much risk nor entertain any apprehensions as to its 

 efficacy, for surely three years will afford them ample time to 

 decide upon its merits and advantage. Its chief features are its 

 expanse and the economy of its arrangement, &c. 



Aware as I am that any information from practical men, expla- 

 natory of the cause of improper working in so many hot water 

 apparatuses, will be acceptable to all gardeners who have the 

 management of them, and who peruse your truly valuable publi- 

 cation. I will briefly state a few of the principal causes to 

 which failures are attributable ; among which none are more dif- 

 ficult to overcome by persons unacquainted with the hydradyna- 

 mic principles on which the action of hot water is regulated, than 

 the accumulation of air in the pipes. Indeed, \mless proper 

 arrangements are made for the escape of the air which is evolved 

 from the water when at a boiling point, no apparatus can act 

 properly. Now, from some accidental cause, even in the best 

 constructed apparatus, this air may collect and lodge in the cor- 

 ners or angles of the pipes, particularly when they have to rise 

 and fall ; this should be particularly attended to, as the want of 

 due regard and necessary precaution in this particular, is in my 

 opinion the principal cause of the many failures with hot water, 

 and the reason why this description of apparatus is sometimes 

 spoken of unfavourably ; for 1 have invariably found from practi- 



