TRANSACTIONS OF THE SECTIONS. l75 



continents. A comparatively high ripening temperature was indeed, among other 

 circumstances, favourable to a high per-cenlage of gluten. There were, however, in- 

 teresting exceptions to this generalization ; at any rate, so far as the per-centage of 

 the nitrogen, if not of the gluten itself, was concerned. 



The foreign wheats containing a high per-centage of gluten, which were generally 

 ripened under a high temperature, had the undoubted character of yielding a flour of 

 great 'strength,' and retaining a considerable amount of water in the bread. Owing, 

 however, to their frequent hardness, and the peculiarity of their structural character 

 generally, which rendered them both refractory in the mill, and less fitted to make 

 an easily workable dough, and a bread of the desired colour, texture, and lightness, 

 they were less valued to use alone for bread-making purposes than many grains of 

 less per-centage of gluten, provided only that they are in an equal condition as to 

 maturation or elaboration of their constituents. Some of the most approved foreign 

 bread-flour grains in the market had indeed a comparatively low per-centage of nitro- 

 gen ; but apparently of very high condition of both their nitrogenous and non-nitro- 

 genous compounds, as well as a very favourable relation to each other of these two 

 classes of constituents. AVithin the limits of our own island, again, on the average of 

 seasons, the better elaborated grain would probably be the less nitrogenous ; though 

 the nitrogenous matter it did contain would be in a high condition as to elaboration, 

 and as to its mutual relations, structural and chemical, with the other constituents of 

 the flour." Hence it came to pass, that as our home-grown flours go, those which 

 were the best in the view of the baker would frequently be those having a compara- 

 tively lovf per-centage of nitrogenous compounds, a higher condition more than com- 

 pensating for the higher per-centage of nitrogen, generally associated as it was in our 

 climate with an inferior degree of development and maturation of the grain. 



The authors further maintained, that the high per-centage of nitrogen or gluten in 

 wheaten-flour was no more an unconditional measure of value to the consumer, than 

 it was in the view of the baker. 



In illustration of this latter point, a Table was exhibited showing the relation of 

 nitrogen to carbon in a number of current articles of food. It was submitted, that 

 the under-fed or chiefly bread-fed working man, would, as his means increased, ge- 

 nerally first have recourse to the addition of bacon, or other highly fatty matters ; 

 which, though they might increase the actual amount of nitrogen consumed, would 

 seldom increase, and frequently decrease, the proportion of the nitrogenous or flesh- 

 forming to the more exclusively respiratory and fat-forming constituents. Indeed, so 

 large was the amount of fat, and therefore of respirable hydrogen, as well as respirable 

 carbon, even in fresh meat itself, that by its use the proportion of the nitrogenous to 

 the other constituents would be much less augmented than might be generally sup- 

 posed. 



On the Correlation of the North American and British Paleeozoic Strata. By 

 Henry Darwin Rogers, Corresp. Memb. of the British Association, Hon. 

 F.R.S.E., F.G.S. 8(c. 



The paleeozoic system of strata constituting the first term in the great succession 

 of fossiliferous deposits of the globe, surpasses in geological interest all other groups 

 of rocks. It is from it that we learn under what types animal and vegetable existence 

 appeared in the morning of the great day of life, which is only now culminating 

 towards its noon. The classification of the palaeozoic deposits, only another expres- 

 sion for the determination of their true chronology, assumes in this light a high im- 

 portance, since through it alone can we trace the physical history of our earth through 

 the most interesting of all its phases, that of the infancy of its inhabitants ; but a 

 sound classification and correct chronology are not to be reached but through a compa- 

 rison of the sediments and fossils of very wide areas, indeed, not until the contents 

 of several great ancient contemporaneous basins have been faithfully coordinated. 

 This consideration confers an especial interest at the present time, upon the study of 

 the palaeozoic fields of North America, which constitute, apparently, five-sixths of 

 that wide continent, and possess, from their very breadth of distribution and amazing 

 continuity of mineral and organic type, unusual value for such comparison. Their title 

 to the attention of the philosophical geologist will be admitted when he reflects, — 

 1st, on the remoteness and apparently partial original insulation of the North Ame- 

 rican palaeozoic basin from the European one ; 2ndly, on their amplitude and unbroken 



