Au£^. 8, 1872] 



NATURE 



283 



It is probable, indeed, that in telegraphing froni one 

 suburb to another the message has to be oftener retrans- 

 mitted than in going from the City of London to India or 

 America, Ijecause a direct transmission from any one part 

 of London to another would involve almost an infinite 

 number of line-wires in all directions. For this reason 

 there must be a limit to the applicability of the Electric 

 Telegraphs in populous districts, and it behoves us to 

 examine whether another agent may not be preferable in 

 dealing with a traffic of this description. The pneumatic 

 tube seems to be well adapted to these circumstances, and 

 having been first applied for short distances by Latimer 

 Clark, and subsequently modified and extended by others, 

 it will faU within the province of our society to examine 

 fully into this and kindred methods that may be devised 

 for effecting rapid interchange of intelligence in towns. 



THE BRITISH COAL-FIELDS 



/^NE distinguished geologist, at least, disbelieves in 

 ^-^ the speedy exhaustion of our coal-measures, sd 

 frequently predicted of late. At the annual, meeting of 

 the Dudley and Midland Geological and Scientific So- 

 ciety, Prof. Ramsay delivered an address on the existence 

 of coal beneath the New Red and Permian strata, in the 

 course of which he observed that for fifteen years he had 

 been preparing to attack this subject, but it w-as not until 

 he became a member of the Royal Coal Commission he 

 had given it a really searching consideration. There 

 could be no doubt that the various coal-fields of the 

 Northern and Midland districts once formed one great 

 coal-field, but had been separated by extensive denuda- 

 tion. Another great coal-field was formed by the now 

 distinct fields of Devonshire, South Wales, Somerset- 

 shire, and the Forest of Dean. Between these two great 

 divisions, the north and the south, there was no connec- 

 tion formed by the coal-measures, the poorer measures 

 possibly having been deposited there, but not the rich 

 deep ones in the carboniferous era. Referring more 

 especially to the Midland district, he thought it highly 

 probable that coal-measures would be found to exist 

 between the present boundary of the South Staffordshire 

 district and the Forest of Wyre ; but it was questionable 

 whether it would be of a workable depth. On the west 

 side of the South Staftbrdshire boundary, in the direction 

 of Bridgenorth, Shropshire, he also believed coal to exist 

 beneath the Permian strata, at a depth of 1,500 feet, or 

 possibly more in some places. At the north of the South 

 Staffordshire boundary, a line drawn from Wyrley right 

 across to the Shropshire district would, he believed, in- 

 clude some valuable coal-beds, a considerable part, but 

 not all, of which would be at a workable depth. He 

 entertained no doubt that the coal-measures were con- 

 tinuous between the South Staffordshire and Shropshire 

 districts, which, although in some places disturbed by 

 denudations, 'might, throughout the greater part of tlie 

 area, be profitably worked. In the North Warwickshire 

 coal-field were found, in the direction of the Staffordshire 

 boundary, five beds of coal, which gradually amalgamated, 

 until on nearing Coventry they formed only two measures. 

 The shale and sandstone were split up in like manner. 

 These features constituted most important evidence in 

 support of the theory that the Warwickshire, Stafford- 

 shire, and Shropshire districts were united by continuous 

 coal-measures, the peculiarities referred to in the coal, 

 shale, and sandstone strata being identical in all three 

 districts. In that theory Prof. Ramsay was a firm believer. 

 From Warwickshire to the south end of the South Staf- 

 fordshire boundary, there was, he believed, coal, but not 

 profitable. Towards the northern end of the South 

 Staffordshire boundary, however, a line drawn from 

 Coventry would include rich and valuable coal-mea- 

 sures. Between Staffordshire and Leicestershire the 



measures were also, he believed, continuous. From 

 Wales to the Forest of Wyre there was profitable ground ; 

 but from Wyre on to Chirnwood Forest, and cast of that, 

 there were no coals of value. The speaker expressed 

 opinions equally assuring as to the presence of coal under 

 the area lying between the north of the S juth Stafford- 

 shire boundary and the mountain limestones of Derby- 

 shire. In one part of that district— viz., north-west of 

 Cannock Chase— Prof. Ramsay said he should not feel 

 the slightest hesitation in recommending a search for 

 coal ; and his belief in the presence of coal at a workable 

 depth in the neighbourhood of Uttoxeter was equally 

 strong. Now, supposing that his calculations were only 

 approximately correct, the result would be surprising. 

 It would amouat to this — the coal now reckoned as avail- 

 able in the South Staffordshire and Shropshire districts 

 was, in round numbers, 3,201 ,000,000 tons. If his belief 

 were a true one, this supply would be further augmented 

 by 10,000,003,000 ton;. In Warwickshire the proved 

 coal-measures are estimated to yield 458,000,000 tons, 

 and the measures he believed to exist in addition wouli 

 be 2,494.,ooo,ooo, or five times more than the present esti- 

 mate. The Leicestershire field was calculated to possess 

 836,000,000 tons, and this would be supplemented to the 

 extent of 1,790,000,000. What was the case in regard to 

 these districts was, he believed, equally applicable to 

 many other parts of Great Britain. The South Wales, 

 Forest of Dean, Bristol and Somerset districts were ex- 

 ceptions to this rule, the coal there lying in basins caused 

 by denudations, the surrounding measures being de- 

 stroyed. In the Midland districts these small basins are 

 not found, the whole forming one great basin. Lan- 

 cashire, Derby, and the Yorkshire coal-fields were, how- 

 ever, subdivided by the process of denuda'.ion. Still, he 

 had no hesitation in believing that the estuary of the 

 Dee and the Mersey have lying between them beds of 

 coal, although probably at too great a depth to be of 

 practical value. 



MR. TODHUNTER ON THE ARC OF THE 

 MERIDIAN MEASURED IN LAPLAND 



lyj-R. TODHUNTER has forwarded us a reprint from 

 •'■'-'• the " Transactions of the Cambridge Philosophical 

 Society," in which he discusses the observations made 

 in connection with the measurement of the arc of 

 the meridian in Lapland in the last century. He 

 states that having recently had occasion to study the 

 details of the tivo measurements of the arc, he has been 

 surprised to find that the accounts of these operations, al- 

 though written by very distinguished astronomers, contain 

 numerous and serious errors. We must refer our readers 

 to the memoir itself for a complete account of the various 

 points raised, for it is too long for adequate notice in 

 the space at our disposal. A curious pomt, however, is 

 raised as to the effect of theory upon observation in a 

 paragraph which we quote in cxtcnso : — 



"It would be a curious subject of speculation whether 

 the theoretical opinions of persons engaged in geodetical 

 surveys could have exercised any influence on their ob- 

 servations ; I mean of course unconsciously, for it would 

 be wrong to suspect any deliberate unfairness in any ol 

 the operations which I have examined. From a passage 

 in the article ' Figure de li Terre,' by D'AIembert in the 

 original Encyclopt'diL, it would appear that the school of 

 Cassini originally believed that in consequence of the 

 oblate form of the earth, the length of a degree of the 

 meridian looiild decrease Irom the equator to the pole. It 

 seems strange, perhaps, now to suppose that such an error 

 could be seriously maintained ; but there can be no doubt 

 of it ; for example, the error was vehemently maintained 

 by Keill, a ma.t of some reputation, who was ultimately a 



