372 THE GARDENER. [Aug. 



apologise to him for alluding to it; if to the latter, then I ask him 

 what other inference is it possible to draw from the statement referred 

 to, but that the water suffers no diminution of temperature on the way 

 from the boiler to the highest and farthest point of the structure. 

 Next, " C. M." tells us, "it is a well-known fact that a house situated 

 above the level of the others is the hottest, which proves the value of 

 elevation." I must again differ with " C. M." It does not prove the 

 value of elevation; neither does it prove that a quicker circulation 

 takes place in the higher house. It only proves that the hotter water 

 gets there, probably through the apparatus being fitted up on the 

 equalised, mixed, forcing, or on the strata theory of circulation, by 

 some one who advocates sinking the boiler as far as practicable below 

 the main body of the piping, and whose knowledge of heating by hot 

 water extends only a little beyond the fact "that water is water, a 

 liquid, and not iron, stone, lead, or ice." I must also say that it is not 

 " a well-known fact that a house situated above the level of the others 

 is the hottest." If " C. M." will do me the honour of a visit, I will 

 show him that this fact of his is not amongst those " chiels that 

 winna ding." 



The points of practical value to be settled in this discussion are, in 

 my opinion, as follows : Is a continuous rise in the flows, from the top 

 of the boiler to their farthest points of extension in the compartments 

 to be heated, essential to rapid circulation 1 I say No; and in place 

 of being essential, the continuous rise is a hindrance to circulation. 

 Is it necessary or essential to rapid circulation that the top of the 

 boiler should be below the main body of both the flow and return 

 pipes, whether there is only one house to heat or a range of houses 1 

 I again say No, and that any number of compartments in a range can 

 be successfully heated without sinking the bottom of the boiler more 

 than one foot below the level of the lowest floor on which it is neces- 

 sary to place the pipes in any of the divisions composing the range; 

 and further, that this can be done without a dip (that is, dipping and 

 rising again) in the flow. Now if those who differ with me will keep 

 to the points here indicated, it will save valuable space in ' The Gar- 

 dener ' at present; and when the long nights come, perhaps the Editor 

 will find room for us to discuss the side-issues of this watery question. 



J. Hammond. 



Brayton Hall, July 11, 1879. 



I was sure Mr Hammond would be surprised to hear that hot-water engineers 

 and gardeners were perfectly familiar with the system of laying pipes with a con- 

 tinuous direct fall from the top of the boiler down to the return. He is so sur- 

 prised, that he can even yet hardly credit the astounding intelligence. This 

 being a matter of fact about which it is unnecessary to have any discussion, I 

 have simply to inform Mr Hammond, that if he chooses to come to Edinburgh, 

 I will show him places fitted up twelve and twenty years ago in the manner re- 

 ferred to ; and, moreover, my own firm have during the last ten years fitted up a 



