202 Reply to Itemarlcs on Mr. PerJdns's 



readers to refer to the article, which will be found in the 

 Mechanics^ Magazine, vol. xviii. ; and which will be read by 

 all friends of humanity, and by all owners of quarries, and 

 coal or other mines, with intense interest. — Cond. 



AuT. IX. Reply to some Remarlcs made by Mr, Main and the Con- 

 ductor on Mr. Perkins's Mode oj" heating by hot Water. By A. 

 M. Perkins, Esq. 



Sir, 



I BEG, without preface, to answer your correspondent Mr. 

 Main (p. 34.), by stating certain facts. 



The first objection which I shall notice is, that, in conse- 

 quence of the extreme smallness of the tubes, and very small 

 quantity of water, the apparatus cannot have that equality of 

 heat so desirable during night, when the fire is most likely to 

 be neglected. 



I shall answer this objection by referring to the specification 

 of my patent, which describes a furnace of fire-brick, so con- 

 structed as to contain sufficient fuel for any specified time ; 

 and so capable of regulation, that the most equal temperature 

 may be maintained for any number of hours required. 



The apparatus which I first erected was at the villa of 

 J. Horsley Palmer, Esq., at Fulham. This gentleman very 

 liberally tried the first experiment on his own hot-house ; 

 and has, with equal liberality, allowed me to make use of his 

 name to promote the spread of the invention. I therefore 

 copy from his own memoranda, which he gave me at the 

 time, a table that shows how completely the equality of heat 

 was maintained in the hot-house for eight days and nights. 

 A Sixe's differential thermometer was set at nine o'clock every 

 night, and examined at nine o'clock the following morning; 

 the fire was also made up, and not touched during the twelve 

 hours. The result was as follows : — 



1832. 

 March 20. 

 21. 

 22. 

 23. 

 24. 

 23. 

 26. 

 27. 



Average diiFerence 23f 



Temperature 





Temperature 







in the open air. 



in 



1 the hot-house. 





Difference. 



47° 



. 



63° 



. 



16° 



43 



. 



63 



. 



18 



43 



. 



63 



- 



20 



38 



- 



63 



_ 



25 



34 



- 



63 



. 



29 



38 



. 



63 



. 



23 



37 



- 



64 



- 



27 



38 



- 



65 



. 



27 



