Rumford tells us that ‘when these roasters were first proposed, and before their merit was established, many doubts were entertained respecting the taste of the food prepared in them,’ but that, after many practical trials, it was proved that ‘meat of every kind, without any exception, roasted in a roaster, is _better tasted, higher flavoured, and much more juicy and delicate_ than when roasted on a spit before an open fire.’ These italics are in the original, and the testimony of competent judges is quoted. I must describe one experiment in detail. Two legs of mutton from the same carcass made equal in weight before cooking were roasted, one before the fire and the other in a roaster. When cooked, both were weighed, and the joint roasted in the roaster proved to be heavier than the other by 6 per cent. They were brought upon table at the same time, ‘and a large and perfectly unprejudiced company was assembled to eat them.’ Both were found good, but a decided preference given to that cooked in the roaster; ‘it was much more juicy, and was thought better tasted.’ Both were fairly eaten up, nothing remaining of either that was eatable, and the fragments collected. ‘Of the leg of mutton which had been roasted in the roaster, hardly anything visible remained, excepting the bare bone, while a considerable heap was formed of scraps not eatable which remained of that roasted on a spit.’ This was an eloquent experiment; the gain of 6 per cent. tells of juices retained with consequent gain of flavour, tenderness, and digestibility, and the subsequent testimony of the scraps describes the difference in the condition of the tendonous, integumentary portions of the joints, which are just those that present the toughest practical problems to the cook, especially in roasting. But why are these roasters not in general use? Why did they die with their inventor, notwithstanding the fact, mentioned in his essay, that Mr. Hopkins, of Greek Street, Soho, had sold above 200, and others were making them? Those of my readers who have had practical experience in using hot air or in superheating steam, will doubtless have already detected a weak point in the ‘blowpipes.’ When iron pipes are heated to redness, or thereabouts, and a blast of air or steam passes through them, they work admirably for a while, but presently the pipe gives way, for iron is a combustible substance, and burns slowly when heated and supplied with abundant oxygen, either by means of air or water; the latter being decomposed, its hydrogen set free, while its oxygen combines with the iron, and reduces it to friable oxide. Rumford does not appear to have understood this, or he would have made his blowpipes of fire-clay or other refractory non-oxidisable material.