434 Report on the progress of the Horticultural Society, 



has not been in a condition to institute comparative trials of the 

 many schemes for heating which have been proposed of late years ; 

 and the Council are of opinion, that, under any circumstances, it 

 would be a waste of the Society's funds to apply them in furtherance 

 of such projects, unless thev involve some new principle, or present 

 such a deviation from the usual application of principles as would 

 justify the expectation of important results. They have however 

 by no means neglected this subject as the following statement will 

 shew : — 



At the close of the year 1832 Mr. Perkins was employed to 

 apply to a small hothouse, then recently constructed, his method of 

 heating by means of numerous small pipes, which was at that time 

 much talked of as an important invention. After repeated trials, 

 during two or three months, the apparatus having once ex- 

 ploded, and proving at all times unmanageable, the plan was 

 abandoned. 



In the year 1838 one of Mr. Rogers' conical boilers was applied 

 to heating a range of pits 77 feet long, with two inch pipes ; an 

 experiment which completely fulfilled the expectations that were 

 entertained of its efficiency. This led to the adaptation of two 

 similar boilers in the year 1839 to other pits, 154 feet in length, 

 which had previously been heated with a common square boiler, 

 and four inch pipes. Partly in consequence of the old apparatus 

 not having been so perfect as could have been wished, and partly 

 in consequence of the greater temperature to which the boilers 

 were exposed, this experiment was not so satisfactory as the last, 

 but it had the advantage of leading to some important improvements 

 in the construction of the apparatus. 



An attempt was also made in 1838 to heat a small range of pits 

 with hot water pipes warmed by an Arnott stove ; but after the 

 purchase of pipes, and twice fixing the apparatus, the boiler proved 

 so defective as to be unfit for use, and by that time the evidently 

 superior efficiency of Mr. Rogers' conical boiler had rendered it 



