1879] HEATING BY HOT WATER. 473 



rise of the heated water in the same time, if it have only an inclination 

 of 1 foot in 100, as if it had 10 feet to fall in the same length ? If so, 

 all rivers would flow at the same speed. In conclusion, I should be 

 like Mr Makenzie, only too pleased to hear of a system which would 

 give us a quick circulation through a large system of pipes without 

 a deep stoke-hole ; but I fail to find any evidence in either the argu- 

 ments or statements of Mr Hammond to prove that he has made the 

 discovery. Henry J. Pearson. 



Beeston, Notts. 



I daresay both you and most of your readers are heartily tired of this discus- 

 sion. Although the subject is a most important one, it has been well ventilated, 

 aud I think may now be safely left in the hands of those whose business or 

 pleasure lead them to carry into practice the various forms of apparatus 

 recommended. 



Allow me very shortly to notice one or two points brought forward in the 

 several communications which appeared in your last. In reply to one state- 

 ment of Mr Stevens's, in reference to "pressure or gravitation," if he will 

 think the matter out a little further, he will find that this pressure or gravita- 

 tion—which he evidently thinks has nothing to do with the circulation of the 

 water — has not only to do with it, but is the sole aDd only cause of the upward 

 motion in the flow-pipe. I tried to make this plain in my last, and if I have 

 failed it is not because such is not the case, but because of my inability to put 

 the matter in as clear a light as I should have wished. This same inability to 

 simplify a somewhat abstruse subject is no doubt the cause of Mr Stevens's 

 not comprehending my reference to friction. His remarks about it having 

 been proved by "Albion" and others that a continuous ascent is not necessary, 

 are, to say the least of it, misleading. From the very first I admitted that 

 there is no necessity for the pipes having a continuous ascent ; indeed, I do not 

 recollect that any of your correspondents took up this position, — the opposite is 

 the case. Mr Hammond and some others asserted that a continuous or vertical 

 rise is a hindrance to the circulation, and is the cause of repeated failures in 

 the working of hot-water apparatus. I repeat that I can point to many appar- 

 atus, fitted up by my own firm and others, where nearly the whole, as it were, 

 is a return-pipe, while there are others where nearly the whole piping is a flow- 

 pipe, both systems working admirably. There are one or two things in Messrs 

 Hamiltons' letter to which I wish to refer, although I am not particularly alluded 

 to. It must not be concluded that because the houses nearest the boiler heat 

 easiest it establishes any principle. I can conceive several possible explana- 

 tions of this ; and if Messrs Hamilton were to call in a properly -qualified 

 engineer, I have no doubt their apparatus could be made to work quite satis- 

 factorily with very little expense, — at least I know one who would be quite 

 prepared to undertake to do so on the safe principle of "No cure, no pay." 

 If Messrs Hamilton, however, state the quantity of piping correctly at 8500 

 feet, I beg to point out to them that the " Climax" boiler of Messrs Hartley 

 and Sugden (I presume " Barr and Sugden" is a slip — there is no such firm of 

 boiler-makers), of the largest size— viz., 5 feet — is only given out to heat, ap~ 

 proximately , 4000 feet ; and where there are so many circulations, I certainly 

 would never think of loading them above 2500 each. Any amount of failures, 

 through causes probably never suspected, will never prove that, given two 



