1879] HEATING BY HOT WATER. 529 



becoming famous as a hot-water engineer, through his not having the 

 courage to back his opinions by appending his name and address to his 

 papers. J. Hammond. 



Brayton. 



[When we stopped the discussion last month it did not occur to us 

 that Mr Hammond, as the originator of the discussion, had a right to 

 the closing article, hence the insertion of this paper. — Ed.] 



Although the hot-water question has received notice to quit your columns, 

 we trust we may be permitted space to correct a typographical error in your 

 September issue. In stating the number of feet of piping attached to our Twin 

 Climax boilers, we wrote "about 5800 feet." Your compositor, by reversing 

 the two first figures, made it read 8500 feet. We repeat, that these boilers 

 are computed to heat 4000 feet each ; and we believe this statement is based 

 on calculations of high authorities on the subject of hot-water heating — yet 

 Mr Makenzie says, that in our case he would "never think of loading them 

 with above 2500 feet each." 



Since your last issue we have been visited by one of your correspondents, a 

 practical and "qualified" hot-water engineer, who, after a most careful ex- 

 amination of the whole apparatus, failed to find anything materially wrong 

 with the arrangement of the pipes with regard to circulation (according to the 

 principles mentioned and followed by Mr Hammond's opponents), and he 

 arrived at the conclusion that the boilers were too weak for the work they 

 have to do. Since then we have thoroughly tested the power of these boilers. 

 A mild day was chosen — fires put out, pipes allowed to get cold, one boiler 

 shut off, fire re-lighted under the remaining one, heated water turned on to 

 house after house, beginning at the lowest level nearest the boiler, until we 

 had, and still have, 4216 feet of 4" piping heated to hothouse temperature by 

 one boiler : it is only when we require heat in the houses on the higher levels 

 that our real troubles begin. Joseph Hamilton & Sons. 



Wellington Place, Carlisle. 



I did not intend to have anything more to say on this matter, for reasons 

 which I previously stated ; but my apology for having to do so is, that 1 find 

 Mr Makenzie in his last has shown a remarkable disregard for facts, and has, 

 whether intentionally or not, misrepresented and placed me in quite a false 

 position before your readers. This is in reference to what he alleges I stated 

 as to " pressure or gravitation " having nothing to do with the circulation of 

 the water in the pipes. How Mr Makenzie could draw such an inference from 

 the sentence referred to is certainly beyond my comprehension. If Mr Makenzie 

 will take the trouble to refer to p. 327 (July), he will there see that I do think 

 pressure has to do with it, but it is only as a secondary agent ; and how it can 

 be made out to be the "sole and only cause" of circulation, I cannot see. 

 Withdraw the primary cause, the heat— which, rightly or wrongly, we assume 

 to be the motive power — and how long would circulation go on ? Only until 

 the pipes got filled and the water found its level. I think Mr Makenzie 



