Feb. 2 1, 1878] 



NATURE 



335 



ample provisions for Strasburg, utterly nefjlecteJ the university 

 system of the country, and failed to introduce the uniformity of 

 manngement and many other reforms, the need of which is pain- 

 fully ielt since the formation of a united Germany, Prof. Sachs, 

 the well-known botanist, has been raised into the nobility, pos- 

 sibly in recognition of his refusal of a flattering call to Berlin. 



IlANOVKR AND Ai.x-i.a-Chapelle. — The two large poly- 

 technics in these cities show a striking diminution in point of 

 attendance during the past year, a fact which would seem to 

 show that the various technical branches in Germany are being 

 overcrowded. Hanover is attended at present by 725 students 

 and the instructors number 46. Aix-la-Chapelle has suffered a 

 reduction of 200 students in comparison with 1876. 



SOCIETIES AND ACADEMIES 

 London 



Royal Society, January 17. — "New Determination of the 

 Mechanical Equivalent of Ilcat," by J. P. Joule, LL.D., F.R.S. 



An account is given by the author, of the experiments he has 

 recently made, with a view to increase the accuracy of the results 

 given in his former paper, published in the Philosophical Transac- 

 tions for 1850. The result he has now arrived at, from the 

 thermal elTects of the friction of water, is, that taking the unit 

 of heat as that which can raise a pound of water, weighed in 

 vacuo, from 60° to 61° of the mercurial thermometer ; its mecha- 

 nical equivalent, reduced to the sea-level at the latitude of 

 Greenwich, is 772*55 foot-pounds. 



February 7. — "On the Comparison of the Standard Baro- 

 meters of the Royal Observatory, Greenwich, and the Kew 

 Observatory," by G. M. Whipple, B.Sc, F.R.A.S., Superin- 

 tendent of the Kew Observatory. 



Owing to certain statements having been circulated as to a 

 large difference existing between the standard barometers of the 

 above two chief meteorological establishments in this country, 

 the Kew Committee decided to institute a direct comparison 

 between them, by the conveyance of a number of instruments to 

 and fro, several times between the two observatories. 



The author accordingly did this, having made three extended 

 experiments of this nature, details of which are given in the 

 paper, the results being as follows : — 



Mean difference from — 



ist series of 128 comparisons — Greenwich-Kew = + o"ooi6 inch. 

 2nd ,, 144 ,, „ >i ^ + o'ooo/ ,, 



3rd ,, 72 ,j „ ,, = 4- o"coi4 „ 



Final mean of 344 „ ,, ,, = -)- o'coi2 ,, 



Certain experiments were also made to determine the necessary 

 corrections to be applied to the Greenwich barometer on account 

 of inequality of distribution of temperature around it. When 

 these corrections are applied the difference between the two 

 standards is reduced to coooi inch, that is to say, the two 

 instruments virtually agree. 



In conclusion the author tenders his thanks to the Astronomer- 

 Royal, for the facilities he afforded for the prosecution of the 

 experiments, and to Messrs, Ellis and Nash for assistance" they 

 rendered. 



Geological Society, January 23. — Prof. P. Martin Duncan, 

 I'.R.S., president, in the chair.— J. Eunson, C.E., R. C. Forster, 

 Walter Mawer, Richard II. Solly, and the Rev. Arthur Watts, 

 were elected Fellows of the Society. Tiie following communi- 

 cation was read :— On the secondary rocks of Scotland. — Part 

 III. The strata of the Western Coast and Islands, by John W. 

 Judd, F.R.S. , F.G.S., Professor of Geology in the Royal School 

 of Mines. The existence of scattered patches of fossiliferous 

 strata, lying between the old gneisdc rocks and the masses of 

 tertiary lava in the Hebrides, has been known to geologists for 

 more than a century. By Dr. Maculloch, who did so much for 

 tfce elucidation of the interesting district in which they occur, 

 these strata were referred to the lias ; but Sir Roderick Mur- 

 chison showed that several members of the oolitic series were 

 also represented among them. Later researches have added 

 much to our knowledge of the moie accessible of these isolated 

 patches of Jurassic rocks in the Western Highlands. During the 

 seven years in which he has been engaged in the study of these 

 interesting deposits, the author of the present memoir has been 

 able to prove that not only is the Jurassic system very completely 

 represented in the Western Highlands, but that ' associated with 

 it are other deposits representing the carboniferous, poikilitic 

 (permian and trias), and cretaceous deposits, the existence of 



which in this area had not hitherto been suspected ; and by 

 piecing together all the fragments of evidence, he is enabled to 

 show that they belong to a great series of formations, of which 

 the total maximum thickness could have been little, if anything, 

 short of a mile. The relations of the scattered patches of mesozoic 

 strata to the older and newer formations respectively, are of the 

 most interesting and often startling character. Sometimes the 

 secondary rocks are found to have been let down by f?ults, 

 which have placed them thousands of feet below their original 

 situations in the midst of more ancient masses of much harder 

 character. More usually they are found to be buried under 

 many hundreds, or even thousands, of feet of tertiary lavas, or 

 arc seen to have been caught up and inclosed between great 

 intrusive rock-masses belonging to the same period as the super- 

 incumbent volcanic rocks. Occasionally the only evidence which 

 can be obtained concerning them is derived from fragments 

 originally torn from the sides of tertiary volcanic vents, and now 

 found buried in the ruined cinder-cones which mark the sites of 

 those vents. In some cases the mineral characters of the strata 

 have been greatly altered, while their fossils have been occasion- 

 ally wholly obliterated by the action of these same igneous forces 

 during tertiary times. In every case the survival to the present 

 day of the patches of secondary rocks can be shown to be due 

 to a combination of most remarkable accidents ; and a study of 

 the distribution of the fragments shows that the formations to 

 which they belong originally covered an area having a length of 

 120 miles from north to south, and a breadth of fifty miles from 

 east to west. But it is impossible to doubt the former continuity 

 of these secondary deposits of the Hebrides with those of Suther- 

 land to the north-east, with those of Antrim to the south, and 

 with those of England to the south-east. From the present 

 positions of the isolated fragments of the mesozoic rocks, and 

 after a careful study of the causes to which they have owed their 

 escape from total removal by denudation, the author concludes 

 that the greater portion of the British Islands must have once 

 been covered with thousands of feet of secondary deposits. 

 Hence it appeai-s that an enormous amount of denudation has 

 gone, on in the Highlands during tertiary time?, and that the 

 present features of the area must have been, speaking geologically, 

 of comparatively recent production — most of them, indeed, appear- 

 ing to be referable to the pliocene epoch. The alternation of 

 estuarine with marine conditions, which had, on a former occa- 

 sion, been proved to constitute so marked a feature in the Jurassic 

 deposits of the Eastern Highlands is now shown to be almost 

 equally striking in the Western area ; and it is moreover pointed 

 out that the same evidence of the proximity of an old shore-line 

 is exhibited by the series of cretaceous strata in the west. The 

 succession and relations to one another of the series of deposits, 

 now described as occurring in the Western Highlands, is given 

 in the following table : — 



Miocene Volcanic and Tntei-volcanic Rocks, 



OIJ Gneiss Series and Torridon Sandstones. 



