324 Retrospective Criticism. 



becoming stagnant. The stagnation of the air is absolutely impossible in any 

 building having a large cooling surface of glass, and with hot-water pipes giving 

 off heat. As well might the ocean, with its ever-rolling waves, be supposed 

 to stagnate, as the air of a house under these circumstances, whether heated 

 on Mr. Penn's or any other system. The air may become very foul, from the 

 gases given oiF from the plants which the house contains ; but this must also be 

 the case with Mr. Penn's plan in common with all others, unless an express 

 provision be made for a renewal of a portion of the air, which does not appear 

 to be the case in the plan [When it appears desirable to change the air of 

 the house, this is not done by opening the sashes in the usual way, but by 

 taking the stoppers out of two openings into the back drain, which contains 

 the hot-water pipes, &c.] proposed by him. There are, however, some objec- 

 tions to Mr. Penn's system which seem to me to be quite fatal to its adoption, 

 unless he can devise means for obviating the difficulty. By this plan the whole 

 of the pipes are placed in a situation where it is impossible to get at them to 

 remedy any defect which may chance to arise by the fracture of a pipe, the 

 unsoundness of a joint, or other casualty, to which this apparatus, in common 

 with ail others, is occasionally liable. But another and still more important 

 objectioiT appears to me to be, that the tunnel or drain in which these pipes 

 are placed will become the receptacle for all kinds of insects, fungus, decayed 

 leaves, and every other description of unwholesome contamination; and that, 

 however fair without, it will within be " full of all uncleanness." The ex- 

 tremely damp state in which the tunnel is proposed to be kept will materially 

 promote this effect ; and I cannot but think that the insects and the various 

 fungi which will lodge therein will in a short time be sufficient to contaminate 

 the whole atmosphere of.the house and materially injure the plants. Perhaps 

 some of your readers can suggest a remedy for this ,• but, for myself, I do not 

 see how it is to be obviated. In considering the objects which Mr. Penn pro- 

 poses to accomplish by his new arrangement, I cannot think that there is any 

 thing in the plan to justify the great additional expense which must necessarily 

 be the consequence of its adoption. I perfectly agree with what Mr. Rogers 

 stated in your March Number, that in every case where a house is warmed by 

 hot- water pipes the same circulation of air is continually going on as in this 

 method of Mr. Penn's ; and if this be the case, and if the objections I have 

 urged above have any weight, then, I think, every unprejudiced person must 

 arrive at the conclusion that this plan is in reality a retrograde movement in 

 the march of improvement, and one which is by no means likely to stand the 

 vmerring tests of time and experience. — Benjamin Fowler. 7. Palsgrave Place, 

 Strand, April 18. 1840. 



Our readers will bear in mind, that whatever has been said in this Magazine 

 in favour of Mr. Penn's plan has been said by us, and not by Mr. Penn ; and 

 therefore Mr. Penn is by no means obliged to take any notice of what our 

 correspondents state on the subject, whether complimentary or otherwise. It 

 is very natural that those who have been accustomed to heat successfully in 

 the usual manner should be induced to notice a new mode, which we have so 

 strongly recommended as we have done that of Mr. Penn ; and we think it 

 but fair that such parties should be heard in their own defence, and the argu- 

 ments they adduce allowed to have their full effect with the public. We have 

 nothing to add to our account of Mr. Penn's method ; but, from the above 

 letter, it appears necessary to repeat that the air of the house may be renewed 

 at pleasure, by unclosing the apertures which communicate with the drains in 

 which the pipes are laid ; that the pipes are readily repaired, when necessary, 

 by opening the covers to the drains ; and that the circulation of air produced, 

 so far from being the same as the circulation which takes place by any other 

 mode of heating with hot water that we have seen or heard of, amounts to a 

 positive current, which will set in motion a sheet of paper or a handkerchief 

 suspended from the roof, near the opening from which the hot air issues. In 

 short, the circulation by Mr. Penn's mode of heating is as to the circulation 

 by the ordinary mode, as Perkins's mode of boiling water by a double boiler 

 is to the common mode of boilins;. 



I 



