314 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



I October, 



they will not be vertical but inclined to the north. If the change in tlie 

 quaiily of the coal is attributed to the influence of subterranean heat, then 

 the inclination of these lines will serve to point out the direction from which 

 that heat acted, namely, from the north-west of the coal-field. 



Mr. Booker, being called on by the President for some statistical informa- 

 iion, staled that there were 159 blast furnaces in the district employed in 

 smelting iron, and that 550,000 tons of iron were annually manufactured. 

 The coal raised in the district was employed as follows : — 



1,50(1.000 tons annually in the manufacture of iron. 



200,6011 ,, „ ,, „ copper. 



l.'>».00(l „ „ „ „ tin. 



r.'iO.OOO ., employed iu domestic purposes and in agriculture. 

 1,7^)6,000 „ exported. 



4,350,000 tens per annum. 

 At this rate, and supposing the coal to e.\ist only over 100 square miles, 

 there was sufficient for 1,400 years to come. The value of the exports from 

 the district, consisting ofiran,&c.,iu a state of rough manufacture, amounted 

 to 4,000,000/. a year. 



** On the Submerf/ence of Ancient Land in Jl'ales ; the Accumulation of 

 newer Strata around and above it ; and the Re-appearance of the same Land 

 by Elevation and Denudation." By Professor A. C. Kamsav. 



This communication was illustrated by a section, on a true scale, of the 

 rocks near Builth, in Uadnorshire, where the Wenlock shales rest uncon- 

 formably on the Llandeilo flags. The lower rocks must have been elevated 

 previously to the formation of the upper, and their upturned edges must 

 have been worn away by the sea when the upper rocks were deposited or 

 previously. No power is known to exist far below the level of the sea, by 

 which this process could have been effected ; it must have taken j)lace at 

 the sea's level. Thr<iughout Wales the Lower Silurian rocks appear to have 

 been disturbed at one particular period, to have been heaved above water 

 and formed a coast, around which the succeeding rocks were accumulated. 

 Near Bishop's Castle the upheaval of the Llandeilo flags was followed by the 

 deposition of the Caradoc sandstone, which is full of pebbles of the older 

 rocks. After this a subsidence appears to have taken place, the area of the 

 sea was increased, and the Wenlock shale was deposited not only over the 

 Caradoc sandstone, but beyond it, as at Builth, upon the Llandeilo flags ; 

 and in some places the shale rests on greenstone rocks and certain pebbles 

 from it, being in fact a gravelly sea bottom. This depression of the bed of 

 the sea continued also duiing the deposition of the Ludiow rocks, which are 

 conformable to the Wenlock shale ; and there is no marked alteration in the 

 organic remains of the two rocks. The Wenlock shale is 1,500 feet thick, 

 and the Ludlow rocks 3,500 feet ; and as it is certain that their organic 

 remains could not have existed at the depth of 5,000 feet, we must suppose 

 a gradual subsidence of the area, such as is believed to be now taking place 

 amongst some of the coral islands, until 5,000 feet of rocks was accumulated 

 over what had been dry land. The old red sandstone, which has a maximum 

 thickness of 8,000 feet, appears also to have extended over this country, 

 judging by the outliers, at a considerable distance to the north and west. 

 Subsequently, the whole of this series, from the Caradoc sandstone upwards, 

 was removed, and the ancient Silurian strata became the surface of dry land 

 as they had been so long before. It now became a question, what amount 

 of alteration may the Silurian rocks have undergone during the time they 

 were so covered up .' If the same laws regulated the ascent of the internal 

 temperature as at present, namely, 1° for every 54 feet, then the addition of 

 5,000 feet of rock would have raised the temperature by 92°, whilst 9,000 

 feet would have added 100°, and v\ith 11,000 of superincumbent strata the 

 Lower Silurian rocks must have endured an increased temperature of 212°. 

 To influences of this kind may, perhaps, be attributed the crystalline or 

 nsetamorphic condition of some of the more ancient rocks, — as suggested by 

 Sir J. Herschel, in a paper communicated years ago to the Geological Society 

 of Loudon. 



The Dean of Westminster referred to the Portland rock, in which a 

 bed of vegetable soil occurs, full of trunks of trees, and cycadites ; this bed 

 rests on limestone containing ammonites, and is covered by similar marine 

 deposits. Again in the Weald, fossil forests and beds of freshwater shells 

 are found above marine accumulations, and followed hy the greensand and 

 chalk. At the present time wt find peats, and antlers of the red deer, in 

 the bed of the Channel, several miles off Swansea. On the Norfolk coast, 

 and in the English Channel, are found the bones of the elephant, and fossil 

 wood, disinterred from former cliffs by the action of the sea. These, with 

 many other circumstances, were quoted as showing that whilst the sea-level 

 was fixed, the land had sufll'ered depressions and elevations at many periods 

 of time. 



Professor Phillips pointed out the extent of some of these subsidences 

 of the land ; for example, the old red sandstone, 8,000 feet thick, all formed 

 in shallow water, and the coal measures 11,000 feet thick, and added under 

 similar circumstances ; and inquired what condition of the interior of the 

 earth can have admitted of the gra.lual subsidence of such great masses of 

 strata ? According to Mr. Hopkins's statement, it was improbable that the 

 interior would now admit of it. With respect to the augmentation of tem- 

 perature which would follow on the addition of several thousand feet of 

 strata, it should be remembered that the communicatinn of heat from below, 

 through such rocks, was remarkably slow ; and the law of the distribution 

 of internal temperature could not be assumed the same in ancient as in 



modern times. As to the level of the sea remaining unchanged, this was 

 only assumed for security in geological leasiit.iiig ; there was evid'-nce in the 

 Malverns of a sea-level 000 feet above the present, but it was iniiio'.silile to 

 say whether that ancient level was nearer the centre of the earth when 

 formed than now. 



Coast Levels. — Lieut. -Col. Porti.ock communicated some observations on 

 apparent changes in the level of the coast near Portsmouth, and contended 

 tbat, as these evidences of subsidence could be traced back to the most 

 ancient times, so they had continued up to the present day, and expressed 

 his conviction that a parallel might be found in existing nature to all the 

 phenomena of ancient times. It appears that Fort Cumberland, near Ports- 

 mouth, stands on a bank of gravel and sand, and that owing to some new 

 wall made to protect it from the sea, a fresh direction was given to the tide, 

 and a portion of the bank undermined and washed away, in the course of 

 which a thick plank with a bolt was discovered, showing that the basis of the 

 fort had no great antiquity. An artesian well has also been made to supply 

 Blockhouse Fort, which shows, for the first 60 feet nothing but clean 

 shingle, and then a layer of sandy clay, full of common oyster-shells. 



" On the Chemical Character of Steel." By Mr. Nasmvth. 



Were we to assume, as our standard of the importance of any investiga- 

 tion, the relation which the subject of it bears to tlie progress of civilization, 

 there is no one which would reach higher than that which refers to the 

 subject of steel : seeing that it is to our possession of the art of producing 

 that inestimable material that we owe nearly the whole of the arts. 1 am 

 desirous of contributing a few ideas on the subject, with a view to our 

 arriving at more distinct knowledge as to what (in a chemical sense) steel is, 

 and so lay the true basis for iraprovenient in the process of its manufacture. 

 It may be proper to name that steel is formed by surrounding bars of wrought 

 iron with charcoal placed in fire-brick troughs, from which air is excluded, 

 and keeping the iron bars and charcoal in contact, and at a full red beat for 

 several days ; at the end of which time the iron bars are found to be con- 

 verted into steel. What is the nature of the change which the iron has 

 undergone we have no certain knowledge ; the ordinary explanation is, that 

 the iron has absorbed and combined with a portion of the charcoal or 

 carbon, and has in consequence been converted into a carburet of iron. But 

 it has ever been a mystery that on analysis, so very minute and questionable 

 a portion of carbon is exhibited. It appears that the grand error in the 

 above view of the subject consists in our not duly understanding the nature 

 of the change which carbon undergoes in its combination with iron in the 

 formation of steel. Those who aie familiar wiih the process of the conver- 

 sion of iron into steel, must have observed the remarkable change in the 

 outward aspect of the bars of iron, after their conversion — namely, that they 

 are covered with blisters. These blisters indicate the evolution of a very 

 elastic gas, which is set free from the carbon in the act of its combination 

 with the iron. I have the strongest reasons to think that these blisters are 

 the result of the decomposition of the carbon ; whose metallic base enters 

 into union with iron, and forms with it,«n alloy, \\\i\\e the other component 

 element of the carbon is given forth, and so produces in its escape the 

 blisters in question. On this assumption we come to a very interesting 

 question — What is the nature of this gas .' In order to examine this, all 

 that is requisite is to fill a wiought-iron retort with a mixture of pure carbon 

 and iron filings, subject it to a loug-contiuued red heat, and receive the 

 evolved gas over mercury. Having obtained the gas in question in this 

 manner, then permit a piece of polished steel to come in contact with this 

 gas, and in all probability we shall then have reproduced on the surface of 

 the steel a coat of carbon resulting from the re-union of its two elements, 

 namely, that of the metallic base of the carbon then existing in the steel, 

 with the, as yet, unknown gas ; thus synthetically, as well as hy analytic pro- 

 cess, eliminating the true nature of steel, and that of the elements or com. 

 ponents of carbon. 



" On Hydraulic Pressure Engines." By Mr. J. Glyn. 



This paper described the mode of employing the power of waterfalls iu 

 a most useful and important manner — too long neglected in this country, 

 considering the advantages it affords in hilly districts for the <]r4inage of 

 mines. Mr. Glyn brought under their notice the meaus of employiog high 

 falls of water to produce a reciprocating motion by means of a " pressure- 

 engine." The pressure-engine acted by the power of a descending column 

 of water upon the piston of a cylinder to give motion to pumps for 

 raising water to a dill'eient level, or to produce a reciprocating motion for 

 other purposes. The pressure-engine was calculated to give great me- 

 chanical eliect in cases where waterfalls may be found of much too great 

 a height and too small a quantity to be practically brought to bear in a 

 sullicieut degree on water-wheels within the ordinary limits of diameter. 

 The author produced instances of the desired pressure-engine, one of 

 which was constructed about forty years ago in Derbyshire — and which 

 he believed was still at work in Alport IMines, to which it was removed 

 from its original situation. The cylinder was, he believed, 30 inches in 

 diameter. In 1841 Mr. John Taylor advised the application of another 

 and more powerful engine at the Alport Mines, which was made under his 

 (Mr. Glyn's) direction at the Bulterley Ironworks in Derbyshire. This 

 was the most powerful engine that had been made. The cylinder was 50 

 inches in diameter, and the stroke 10 feet. It was worked by a column of 

 water of 132 feet in height, so that the proportion of power to act on it 

 was as the area of a piston to that of the plunger— namely, 1,903 to 1,386, 



