Feb. 



8.] 



SCIENTIFIC NEWS. 



115 



seen with the naked eye, but with quite a small telescope 

 fifty times as many could be seen in the northern hemi- 

 sphere alone. An opera-glass was an excellent instru- 

 ment with which to observe the heavens. There were 

 actual maps containing 324,000 stars in the northern 

 hemisphere, and these could be seen through a small 

 telescope. The stars seen with the naked eye were only 

 an infinitesimal part of those which existed in space. 

 The lecturer gave an interesting demonstration in trigono- 

 metry of the method of measuring the distance of the 

 stars. Astronomers were obliged to resort to the longest 

 base line they could get, and that was the whole orbit of 

 the earth — nearly two hundred million miles. They did 

 this by taking the triangles at an interval of six months. 

 In this way they knew that the nearest star to us — 

 Alpha, in the constellation of the Centaur — was twenty 

 millions of millions of miles distant. It would take three 

 hundred thousand years to count this number, counting 

 fast day and night ; or, if the distance were taken as a 

 railway journey, at a fare of a penny per hundred miles, 

 it would take a hundred and seven million pounds more 

 than the National Debt to pay the fare. The stars of 

 the constellation Hercules appeared to be opening out, 

 and on the opposite side of the sky the stars were found 

 to be drawing together, so that it was concluded that our 

 sun and its planets were bound on a mighty voyage to 

 the constellation Hercules. Twenty thousand miles of 

 that journey had been taken in the fifty minutes that had 

 «lapsed since the beginning of the lecture; but we might 

 travel for millions of years without reaching very far into 

 the confines of that constellation. 



GEOLOGICAL SOCIETY. 

 At the meeting held on January nth, 1888, Prof. J. W. 

 Judd, F.R.S. (President), in the chair, the following com- 

 munications were read : — 



(i) " On the Law that governs the Action of Flowing 

 Streams," by Mr. R. D. Oldham. The author, after 

 describing how his attention was drawn to the subject, 

 proceeded to an investigation of the law that governs the 

 action of a flowing stream. Having accepted as a funda- 

 mental principle that the velocity of a stream will 

 always tend to become such as is just sufficient to trans- 

 port the solid burden cast on to the stream, he finds that, 

 •where untrammelled by exterior conditions, a stream will 

 be alternately confined to a single, well-defined, deep 

 •channel, and spread out into a number of ill-defined, 

 shallow channels, the former being defined as a " reach," 

 the latter as a " fan," that the gradient in the " reach " is 

 less than on the "fan," and that both "reach" and 

 ■" fan " will continually be encroaching at their upper 

 ends, and being encroached upon at their lower ends. 

 After pointing out that what should occur according to 

 ihypothesis, does actually occur in nature, the author 

 said that accepting this agreement of fact with hypo- 

 thesis as proof of the correctness of the latter, it 

 follows that the fundamental principle on which it is 

 founded is correct, and that, in the absence of interfering 

 causes of greater potency, it is the coarseness or fine- 

 ness of the debris cast upon a stream that will determine 

 ■Its gradient and velocity, and not, as stated in text- 

 fbooks, the velocity of a stream that will determine its 

 ■gradient and the coarseness of the debris transported by 

 it :— a conclusion that might be arrived at independently, 

 from the fact that it is in the upper reaches of a stream, 

 where coarse debris prevails, that high velocities of 



current prevail, while in the lower reaches, where the 

 debris is finer in grain, the velocity of current is also 

 diminished. 



(2) " Supplementary Notes on the Stratigraphy of the 

 Bagshot Beds of the London Basin," by the Rev. A. 

 Irving. This paper contained the results of field- 

 work during the year 1S87. Additional notes on the 

 stratigraphy of the Bracknell and Ascot Hills were given, 

 justifying the reading of the country as shown in figs, i 

 and 2 of the author's last paper (Q. J. G. S., August, 

 1887), the examination of this line of country having 

 been extended as far as Englefield Green. The strati- 

 graphy of the hills known as Finchampstead Ridges has 

 been worked out from numerous sections on their flanks; 

 and the strata of the Bearwood Hills were correlated 

 directly with them. All along the northern margin a 

 general attenuation of (a) the lower (fluviatile) sands, 

 of (b) the middle (green earthy) sands was shown to 

 occur, and in some places on the northern margin they 

 are found to have entirely thinned away, admitting of 

 distinct overlap at more than one horizon. 



The second part of the paper dealt with the Highclere 

 district, where the author believes he has established the 

 full succession of the three stages of the Bagshot 

 Formation. 



Some important conclusions were drawn as to the 

 Tertiary physiography of the South of England ; and the 

 revised tabulation of the Tertiaries put forward by Prof. 

 Prestwich at the Society's last meeting was referred to 

 as supporting some of the main points for which the 

 author has contended. 



(3) " The Red-Rock Series of the Devon Coast Sec- 

 tion." By the Rev. A. Irving. 



From a recent examination of this section, and from 

 the facts furnished by Mr. Ussher's paper (Q. J. G. S., 

 vol. xxxii., pp. 367 et seq.), the author has arrived at the 

 conclusion that the series of red rocks between the Lias 

 to the east of Seaton and the Carboniferous of Devon, 

 formerly described under the title of " New Red Sand- 

 stone," cover the period of geologic time which that term 

 signified, and that the lower members of the series belong, 

 not to the Trias, but to the Permian or Post-Carboni- 

 ferous. He considered that at the base oi the Budleigh- 

 Salterton Pebble-bed there is a physical break of as much 

 significance as that between the Trias and the Permian 

 of the Midlands. From this point eastwards the Triassic 

 system is represented by a series ot rocks quite com- 

 parable with the Bunter and Keuper of the Midlands, 

 the Bunter being here represented by the Middle 

 Division (about 200 feet thick) and the Upper Division of 

 Prof. Hull. 



In the marls which underlie the Budleigh-Salterton 

 Pebble-bed, he recognised the equivalents of the Permian 

 Marls of Warwickshire and Nottinghamshire, and of the 

 Zechstein Marls of Germany. These pass, by a gradual 

 transition, through Sandstones, becoming more and 

 more brecciated, into the great brecciated series ot 

 Dawlish and Teignmouth, which were regarded as the 

 equivalents of the great Permian breccias of the west ot 

 England, of Ireland, and of the Lower Rothliegendes ot 

 Germany. 



All the rocks below the Budleigh-Salterton Pebble-bed 

 were regarded as the assorted materials furnished by the 

 detritus of the palaeozoic mountain-region of Devon, 

 Cornwall, and Brittany, and as representing the waste 

 and degradation of that region, deposited on the moun- 

 tain-flanks and in land-locked bays during Post-Carboni- 



