5 i2 THE POPULAR SCIENCE MONTHLY. 



meat, soup is merely a luxury, not a necessary element of complete 

 dietary. 



What we call boiled meat, as a boiled leg of mutton or round of 

 beef, is an intermediate preparation. The heat is here communicated 

 by water and the juices partially retained. 



Note. A correspondent tells me that he has tried the method of cooking eggs which 

 I recommended, and he states that his eggs " were not cooked at all." From what I can 

 learn by his letter, he omitted to attend to the quantity of water I named, viz., about a 

 pint. 



As this is of essential importance, I should perhaps have stated it with some em- 

 phasis. More than a pint of water should be used rather than less, as upon the quantity 

 of water depends the retention of the heat. If the quantity of water is smaller, it should 

 be kept boiling about half a minute before setting aside. 



VIII. 



The application of the principles already expounded to the pro- 

 cesses of grilling and roasting is simple enough. As the meat is to be 

 stewed in its own juices, it is evident that these juices must be retained 

 as completely as possible, and that in order to succeed in this we have 

 to struggle with the evaporating energy of the "dry heat" which 

 effects the cookery. 



It should be clearly understood that the so-called " dry heat " may 

 be communicated by convection or by radiation, or both. "When water 

 is the heating medium, there is convection only, i. e., heating by actual 

 contact with the heated body. In roasting and grilling there is also 

 some convection-heating due to the hot air which actually touches the 

 meat ; but this is a very small element of efficiency, the work being 

 chiefly done, when well done, by the heat which is radiated from the 

 fire directly to the surface of the meat, and which, in the case of roast- 

 ing in front of a fire, passes through the intervening air with very 

 little heating effect thereon. 



I am not perpetrating any far-fetched pedantry in pointing out this 

 difference, as will be understood at once by supposing that a beef- 

 steak should be cooked by suspending it in a chamber filled with hot 

 dry air. Such air is actively thirsting for the vapor of water, and will 

 take into itself, from every humid substance it touches, a quantity 

 proportionate to its temperature. The steak receiving its heat by 

 convection, i. e., the heat conveyed by such hot air, and communicated 

 by contact, would be desiccated, but not cooked. 



This distinction is so important that I will illustrate it still further, 

 my chief justification for such insistence being that even Rumford 

 himself evidently failed to understand it, and it has been generally 

 misunderstood or neglected. 



Let us suppose the hot air used for convection cooking to be at the 

 cooking-point, as the hot water in stewing should be, what will follow 

 its application to the meat? Evaporation of the water in the juices, 

 and with that evaporation a lowering of temperature at the surface of 



