Retrospective Criticism. 4-3 



long after the water ceases to circulate; therefore, the pipes ought in every 

 case to be placed inside of the house or houses to be heated. Knowing how 

 willingly jou give publicity to every improvement, I trust you will insert this 

 correction, as it may prevent disappointment, and do justice to a system that 

 when properljr constructed is preferable to all others. — N. M. T. Folkestone, 

 Dec. 8. 1840. 



Air. Pemi's Mode of Heating, as contrasted luitli other Alodes. — I think it is 

 much to be regretted that Mr. Penn did not prevent the possibility of mis- 

 construction by taking out a patent, and keeping it in his own hand till per- 

 fectly understood, thereby securing it to the public with every improvement 

 that experience might suggest. But he has given up his indisputable right 

 to do this, and has apparently gained nothing in return — no, not even 

 the thanks of those who might have profited most by his, as it appears, ill- 

 bestowed liberality. Having by leaving his invention open for the good of the 

 public waived all claims to the golden harvest it must otherwise have produced 

 him, it might reasonably be supposed that he would have been allowed full 

 credit for his ingenuity. To retain the shadow, after so generously parting 

 with the substance, is even denied him. jNIr. Fowler, in his paper on the 

 subject, Vol. for 1840, p. 323., says it is no invention ; still he insists on having 

 this nothing divided, and proposes to share the palm with Mr. Beaton, by 

 which it is evident that he considers discovery and invention the same thing. 

 I think the two modes very different, and consider that had Mr, Beaton or 

 any other man, by erecting an apparatus to answer any other purpose, found 

 out Mr. Penn's sj-stem, it would have amounted to a discover}-, an accidental 

 discovery only, an effect produced, without, in all probability, the producer 

 being able to define the cause. How different is the case with reference to 

 ISIr. Penn ! He saw the desirableness of the revolution he has effected, 

 directed the energies of a vigorous mind to produce it, and the result has 

 been his system as it now stands, based upon unerring principles, effective, 

 grand, and simple. All this, says Mr. Fowler, is as new as chimneys, which he 

 informs us were invented by the good people of the thirteenth century, by 

 which it is evident that they knew that " sparks fly upwards," and probably 

 that they knew hot air ascended also ; but, if they had not found out this, 

 many a poor gardener, to his cost, had been left to the necessity of turning 

 every sash into a chimney that the smoke might escape into the atmosphere. 

 Thus, in these matters, according to Mr. Fowler, we have been stationary 

 since the thirteenth century ; and all parties might have been as fully 

 satisfied with the chimney system as he is, and we might have remained so for 

 thirteen centuries more. But Mr. Penn has at length grasped this column of 

 heated air, hitherto stubborn as the monument, and bent it to his purpose, 

 making his invention, as Mr. Fowler has unwittingly expressed it, a truly 

 retrograde movement. The air of a house, Mr. Fowler observes, heated 

 by pipes, cannot become stagnant ; the same with equal justice may be said of 

 the most stagnant pond that fosters pestilence : still, strictly speaking, this is 

 correct ; practically speaking, it is sheer nonsense. The air of such houses 

 is often stagnant, palpably stagnant, to a degree highly injurious to the in- 

 terests of the cultivator ; yet in the same breath Mr, Fowler informs us that 

 the air in Mr. Penn's houses must become so, and forthwith consigns it a 

 habitat in the drains ! Yes, in the drains, the current that rushes through 

 which and agitates the waves of this ocean is compared to the force of the 

 whirlwind, the rage of the tornado. Had there been a possibility of what he 

 surmised happening, it would have shown a much better feeling to have pro- 

 posed a remedy, than to have opposed by " weighty objections" a plan, which, 

 at the time he wrote, it is evident he knew nothing about. These weighty 

 objections are, I may add, probably the most harmless things that ever 

 assumed so formidable a name, as, according to his own showing, they could 

 not possibly exist. — N. AI. T. Folkestone, Dec. 9. 1840. 



Mr. Rogers's Conical Boiler. — As my sole object, with reference to the 



