31 



HOT ^yATER BOILERS. 



We consider that to arrange a complete hot water apparatus, some 

 attention ought to be paid to adapt the boiler to the circumstances of the 

 case. This we beUeve has been too httle attended to, and of course some 

 of the features attending heating by this means may be safely attributed 

 to a disregard to some fixed principle in this respect. On this subject 

 Mr. Hood, already quoted, obsei-ves, In adapting the boiler to a hot 

 water apparatus, it is not necessary, as is the case with a steam boiler, to 

 have its capacity exactly proportional to that of the total quantity of pipe 

 which is attached to it ; on the contrary, it is sometimes desirable even 

 to invert this order, and to attach a boiler of small capacity to pipes of 

 large size. It is not however meant, in recommending a boiler of small 

 capacity, to propose also that it should be of small superficies ; for it is 

 indispensable that it should present a large sm-face to the fire, because, 

 in every case, the larger the smface on which the fire acts, the greater 

 will be the economy of fuel, and therefore, the greater will be the effect of 

 the apparatus. 



The following figm'es of boilers are those in common use, and each has 

 of course its pecuhai' advantages and defects. 



Figure 1 is the form first used by Mr. Atldnson, and in many cases 

 such a form is still used by that gentleman and by others. Its advantages, 

 like those of 2 and 3, are, that when the water in them is once heated, 

 they retain their heat longer. Their disadvantages, on the other hand, 

 are, that although it is true in fact that such boilers retain their heat 

 longer than some others do, yet that is not a sufiicient reason for their 



