228 Retrospective Criticism, 



absorb it, and steam is soon produced. There is a small pipe fixed in the top 

 of the boiler, with a steam valve to guard against accidents. By close atten- 

 tion to the fuel and damper, this steam might be avoided, and only as much 

 heat produced as could be absorbed by the water ; but this requires too great 

 a nicety for so simple an apparatus. Instead of having the inner part of the 

 boiler a cone, let us have it more of a cylindrical form ; this would reduce 

 the size of the fire and the surface to be heated, and it would increase the 

 space for the water in the same ratio. Probably some modification of this 

 kind would simplify the working of the boiler, by producing no more heat than 

 is absorbed by the water. At any rate, we must get rid of the steam, at least 

 till the water in all the pipes is heated to 200°." 



The misapprehension iVIr. Beaton appears to be under with respect to the 

 steam, is as to the cause of its generation. This does not proceed from the 

 heat being generated too fast for its absorption by the water, but by the exist- 

 ence of a vacuum somewhere either in the boiler or pipes, most probably in 

 the latter, and the communication between the hottest and coolest parts of 

 the water intercepted. In order to correct it, he must contrive to have the 

 whole body of piping completely filled, and the supply-tank partly full, before 

 he lights the fire. If this be done, the effect of the application of heat is to 

 set the water in motion where it is in contact with the fire, causing it to 

 circulate through all its extent, until it is returned in a cooler state to the 

 boiler to undergo successively the same operation. To effect this, attention 

 must be paid to the air-cock, if there is one ; if not, holes must be drilled in 

 the higher parts of the pipes to allow the air to escape, and the water to show 

 itself running out of the orifice ; which holes any blacksmith can drill, and 

 they may be closed by simple plugs. In order to have the most advantageous 

 result, the water ought not to boil, but stop short of that degree of heat, say 

 200°; and, to make this most excellent apparatus perfect, the manufacturer 

 should estimate the exact quantity of pipe each size will heat to that temper- 

 ature. I believe it would be better to have nothing to do with steaming the 

 house from it, but that a simple machine should be made for the purpose, as 

 suggested by Mr. Beaton, whose idea of steaming houses, either simply or 

 with tobacco, I think admirable, and most easy of adoption, possibly by 

 simpler and more economical means than even that which he recommends. If, 

 however, it be thought advisable to use Rogers's apparatus for that purpose, 

 care should be taken to have a complete stop-cock, so as to separate the pipes 

 entirely from the boiler during the operation. By preventing the water in the 

 pipes from being heated to a point short of boiling, little waste of water takes 

 place, and the tank should be in such a situation that it may always insure a 

 supply sufficient to keep the pipes full. 



I do not see the advantage Mr. Rogers states, of having the pipes very 

 much higher than the boiler, which may either entail a necessity of sinking 

 the boiler deeper than is convenient, or of raising the pipes above the ground 

 level, about which they ought to lie, and always at the outside or near the 

 point of the greatest cooling surface. I should think one foot, his minimum, 

 quite sufficient, and doubt there being any advantage in having them higher. 

 It is evident there must be a maximum, and that a given quantity of fuel, how- 

 ever applied, can only heat a certain quantity of water; but it is a very consi. 

 derable quantity, with such an apparatus as this, if confined as here stated, 

 and no waste allowed by generation of steam. The parties alluded to by Mr. 

 Rogers, instead of forcing fire upon the boiler, had better have increased the 

 quantity of piping, and consequently the radiation of heat. If any part be 

 defective, or rather if the air be confined in any part of the pipes, it will be 

 discovered by that part remaining cool when the water short of it in the cir- 

 culation is hot, and an opening should be immediately made. 



Having explained the mistake on which the reasoning of Mr. Beaton ap- 

 pears to be founded, his recommendation of an alteration in the form of the 

 boiler becomes unnecessary. In fact, the cylindrical form would be worse 

 than the present, and the reverse of any advantage gained by the adoption 



