Dec. 26, 1878] 



NATURE 



"f^n 



I may now discuss the third meritorious feature which 

 Dr. Dauglish regarded as a conspicuous advantage pos- 

 sessed by his process — a view which is now endorsed by 

 Dr. Richardson, We are told that "in brown bread, 

 which contains the envelopes or coverings of the whole 

 grain, the flesh-formers amount to 10 per cent., and that, 

 while it is possible to live upon brown bread, without any 

 other food, the health suffers, and death finally ensues, 

 on white bread alone." "The flesh-formers in white 

 bread amount," we are told, " to 7 or 8 per cent.'"' Now 

 by the use of the aerating process, a light and palatable 

 loaf may undoubtedly be readily made, either from the 

 entire rneal of crushed wheat, or from such meal from 

 which nothing but the long or coarse bi-an has been 

 excluded. Such a result cannot be secured with any 

 degree of certainty when yeast is used. This is quite 

 true. But it is not by any means an ascertained fact 

 that brown bread or whole meal bread contains a 

 larger proportion of flesh-formers than white bread 

 from the same wheat. If we make no deduction on 

 account of insoluble and inaccessible flesh-formers in 

 the coverings of the grain, we shall have to make 

 a very considerable deduction on account of nitrogenous 

 matters which are not really albuminoid or flesh-forming, 

 and which are extensively present in the coats which 

 form the main substance of pollard and sharps. We can 

 hardly attribute flesh-forming properties to the "dias- 

 tase," "cerealin," and other obscure nitrogenous fer- 

 ments which we know to abound in the coarser mill 

 products. Now these are the very bodies which the 

 aerating process enables us to include in our bread without 

 making it heavy, the very bodies whose presence con- 

 tributes most largely to raise the percentage of assumed 

 flesh-formers, from the 7 or 8 per cent, in white 

 bread to the 10 per cent, in real brown bread. Now, 

 although we have no absolute method of distinguishing 

 between the true flesh-forming nitrogenous bodies in 

 food-stufts and those whose value is at the best problem- 

 atical, yet the "carbolic acid process" which I devised 

 in 1873, and which has latterly been attracting a good 

 deal of attention, furnishes some instructive results when 

 applied to the various mill products of the cereals. For 

 instance, I found (in 1875) that pearl barley contains at 

 least 92 per cent, of its nitrogen in the form of genuine 

 coagulable albuminoids, but that ''fine dust," consisting 

 of the richest parts of the barley grains, though it contains 

 three times as much nitrogen as pearl barley, does not 

 contain twice as much unmistakable flesh-forming sub- 

 stance. A similar observation was made on comparing 

 the coverings of the wheat grain with the flour— 93 parts 

 out of every 100 of nitrogen in ordinary wheaten flour 

 being certainly in the form of flesh-producers, while the 

 proportion in the entire bran sinks to an average of 72, 

 and sometimes touches a much lower figure. The same 

 result has been obtained with a large number of food 

 materials, in some succulent vegetables the albuminoid 

 nitrogen not exceeding one-fifth of the whole. 



It is evident, from the preceding considerations, that 

 whatever be the nutritive or medicinal merits of whole- 

 meal bread, it cannot be definitely stated to be a much 

 richer food so far as flesh-formers are concerned, than 

 white bread made from the flour of the same sample of 

 wheat grain. If we deduct from the supposed 10 per cent, 

 of flesh-formers in whole meal bread \ox 2 per cent, because 

 of the existence of non-albuminoid nitrogen in the branny 

 particles, and because of the indigestible condition of a 

 small part of the true albuminoids, we leave but 8 per 

 cent, a proportion which does not greatly exceed the 7 or 

 7* per cent, usually attributed to white wheaten bread. 



On some future occasion I may have a few words to 

 say, should the Editor of Nature accord his permission, 

 as to the bread question treated of in the "Dietaries of 

 Prisons' Report," lately presented to Parliament. 



A. H. Church 



ON 



THE COMBUSTION OF DIFFERENT 

 KINDS OF FUEL 



OUR attention has been called to this subject on 

 perusing a paper read before the American Institute 

 of Mining Engineers. In this communication it is 

 attempted to be proved, that the manner in which char- 

 coal unites with oxygen in iron furnaces, explains its 

 alleged superiority over mineral coal. 



The question appears to us to involve considerations 

 outside the mere technical limits of iron smelting. We 

 therefore submit the following remarks, which have been 

 prepared at our request, by a gentleman whose important 

 researches on the economic application of fuel in the 

 smelting of iron are known to all the world. — Ed. 

 Nature. 



Prof. John A. Church, of Columbus, states, in a recent 

 publication, " that it is a well-known fact that under 

 similar conditions a ton of pig-iron can be made from 

 any ore with less fuel when charcoal is used than when 

 coke or anthracite is employed for heating." He then 

 discards, as untenable, all former explanations of this 

 doctrine proceeding either from scientific or practical 

 men, and maintains that "the highest carbon duty is 

 given by the fuel which withdraws the most oxygen from 

 the blast in a gfiven time." 



The professor afterwards proceeds to explain that char- 

 coal, being highly porous, presents a more extended sur- 

 face to the action of the oxygen than the more compact 

 forms of carbon as it exists in coke or anthracite. He 

 then considers the effect of what is designated in the 

 paper as diluted oxygen on its way to the upper regions 

 of the blast furnace. 



In this latter statement with regard to free oxygen, it 

 seems to be overlooked that whatever difficulty this gas 

 may have in attacking dense carbon, there can be no 

 reason why carbonic oxide, generated from coke or 

 anthracite, should not be as easily burnt to the state of 

 carbonic acid as the same carbonic oxide is burnt when 

 formed by the combustion of charcoal. 



If it could be shown that all the carbon consumed in 

 the hearth of the blast furnace were in the condition ot 

 carbonic acid, then, no doubt, free oxygen might be 

 expected there, but in the presence of so vast a volume 

 of inflammable carbonic oxide in that region such a con- 

 dition of things is scarcely possible. 



It is unnecessar)-, however, to occupy space with merely 

 speculative matter when actual analyses inform us that 

 in a furnace using coke, not only is there no free oxygen 

 at a very short distance from the tuyeres, but that there 

 is no carbonic acid. In point of fact the whole of the 

 gaseous carbon exists there in the form of carbonic oxide. 



Admitting, then, the highest carbon duty to be dependent 

 on the law laid down in the paper, it is clear that at a 

 distance of two or three feet from the point where the 

 blast enters, the conditions in this respect of a furnace 

 burning charcoal or coke are the same. 



Prof. Church quotes, in the course of his observations, 

 the results obtained from two furnaces, one using char- 

 coal the other anthracite, and from these he infers that 

 there is an " inherent difference " between the two kinds 

 of fuel of 900 lbs. per ton of iron in favour of charcoal. 

 This figure is a mighty one when it is considered that the 

 charcoal actually consumed for each ton of pig is under 

 1,800 lbs. 



Somewhat inconsistent with this conclusion is the in- 

 stance quoted of a Lake Champlain furnace, where the 

 consumption of anthracite has been reduced nearly 25 

 per cent, below that quantity which formed the basis 

 upon which the " inherent difference" was estimated. 



The paper further recommends as a reasonable con- 

 sequence I f the superiority of charcoal over coke, that 

 iron manufacturers should, as far as possible, imitate the 

 physical structure of the former in the produce of their 



