THE CHEMISTRY OF COOKERY. 593 



pany 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 six per cent gained tell of 

 juices retained with consequent gain of flavor, tenderness, and diges- 

 tibility, and the subsequent testimony of the scraps describes the dif- 

 ference 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 ? I will take up these questions in my next. 



XII. 



Returning to the question suggested by my last paper, Why has 

 Rumford's roaster fallen into disuse, notwithstanding the fact, men- 

 tioned in his essay, that Mr. Hopkins, of Greek Street, Soho, had sold 

 above two hundred, 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 " blow-pipes." When iron pipes are heated to 

 redness, or thereabout, 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 blow- 

 pipes of fire-clay or other refractory non-oxidizable material. 



The records of the Great Seal Office contain specifications of hun- 

 dreds of ingenious inventions that have failed most vexatiously from 

 this defect ; and I could tell of joint-stock companies that have been 

 "floated" to carry out inventions involving the use of heated air or 

 superheated steam that have worked beautifully and with apparent 

 economy while the shares were in the market, and then collapsed just 

 when the calls were paid up, the cost of renewal of super-heaters and 

 hot-air chambers having worse than annulled the economy of working 

 fuel described in the prospectus. Thus a vessel driven by heated air,, 

 as a substitute for steam, was fitted up with its caloric engine, and 

 crossed the Atlantic with passengers on board. The voyage practi- 

 cally demonstrated a great saving of coal ; patent rights were pur- 

 chased accordingly for a very large amount, and shares went up buoy- 

 vol. xxiii. 38 



