104 



NA TURE 



[June 3, 1897 



Certain final corrections, which had the same values for 

 all trials, were made to the mean value of J, already given. 

 These were introduced on the following various counts : — 



I, Length of the brake lever (o'ooo42). 



II. Salts dissolved in Manchester water (o"00003). 



III. Air dissolved in water used in the trials ( - o'ooo2i). 



IV. Reduction of weighings to vacuo ( - 0'ooi2o). 

 V. Varying specific heat of water ( - o"oooo6). 



VI. Pressure on thermometer bulbs ( -0'00037). 

 VII. Work done against gravity (o"oooo7). 

 VIII. Engagement of counter (o'ooooi). 



Their total effect was to introduce a correction factor of 

 (i -0-00125). 



The mean corrected value of the specific heat of water 

 between freezing and boiling points, as measured in 

 mechanical units at Manchester, is found to be 776-94. 



THE INTERNATIONAL GEOLOGICAL CON- 

 GRESS IN RUSSIA. 

 THE Intefnational Geological Congress may be said 

 to come of age this year, for it was founded at 

 Philadelphia in 1876, at a meeting held under the presi- 

 dency of the veteran James Hall. The first organised 

 session was held at Paris in 1878, and since then meet- 

 ings have taken place at Bologna, Berlin, London, 

 Washington, and Ziirich. The seventh session is to be 

 held at St. Petersburg, with Prof A. Karpinsky as 

 President. 



The ordinary meetings of the Congress will be held in 

 the rooms of the Imperial Academy of Sciences at St. 

 Petersburg. There will be a preliminary assembly of the 

 members on August 28, the formal opening will take 

 place on the following day, and the meeting will terminate 

 on September 4. According to the Russian Calendar 

 these dates will Ije twelve days earlier, namely, August 16, 

 17, and 23. 



The meetings will extend over eight hours. From 

 9 till 10 a.m. the Committees of the Congress will 

 dehberate ; from 10 till 2 p.m. there will be discussions 

 on questions proposed in the programme of the Organ- 

 ising Committee. One hour is then set aside for visits to 

 museums and to the exhibition of maps, sections, books, 

 specimens and instruments — possibly some members 

 may then take the opportunity of obtaining lunch. From 

 3 to 5 o'clock papers of a general character will be 

 read, and these will be so arranged that only one branch 

 of geological science will be discussed each day. 



The Organising Committee will reopen the subject of 

 the unification of geological nomenclature. The larger 

 divisions of the earth's history must be based on general 

 palceontological characters, and in defining the several 

 systems attention will be specially given to the study of 

 pelagic life and the evidences of organic evolution. In 

 order that a system be well established it must be capable 

 of subdivision into stages characterised by well-marked 

 pelagic faunas, and these should have a European or 

 equivalent value. It is recognised that sub-stages have 

 only a regional value, while minor divisions have but a 

 local character, and with these the Congress does not 

 deal. The divisions, in short, which the assembly will 

 be called upon to discuss are those of geological time, 

 based on the occurrence of successive groups and zones 

 of fossils ; the purely stratigraphical divisions are essen- 

 tially regional or local, and they may reasonably be left 

 for each country to fix according to its own necessities ; 

 for they are all important in the interpretation of the 

 structure of a district, in determining its economic re- 

 sources, and in explaining the origin of its scenery. On 

 the other hand, when we seek to trace out the history of 

 the great changes which the earth at large has under- 

 gone, the more comprehensive life-divisions are all 



NO. 1440, VOL. 56] 



important ; and these only can be universally applied, 

 and, we hope, universally adopted. It is true that life- 

 divisions are no more to be rigidly defined than are 

 stratigraphical divisions in the rocks, but fossils are the 

 only guides for correlating the formations in countries far 

 apart. There should be no serious disagreement among 

 geologists, at any rate, with regard to the principles of 

 correlation ; and there is no reason why, after full and 

 friendly discussion, a particular nomenclature should not 

 be generally accepted. It need not interfere with our 

 local divisions, any more than great chronological terms, 

 if applied to human history in general, would interfere 

 with our own time-divisions marked by the reigns of 

 successive monarchs. 



The Organising Committee will also deal with the 

 subject of petrographic nomenclature, in the hope of re- 

 ducing the number of terms now used, and of preventing 

 unnecessary names being introduced. In petrology, as 

 in palaeontology, one is nowadays in constant need of a 

 dictionary or glossary, or table of synonyms, to under- 

 stand the various names of rocks or rock-structures and 

 fossils. 



The scheme for Excursions in connection with the 

 Congress is an elaborate one. There will be excursions 

 both before and after the ordinary meeting, and those 

 who have time and money will have grand opportunities 

 of visiting many parts of the Russian empire in 

 Europe. 



Prior to the Congress there will be three excursions ; 

 namely, to the Ural regions, to Esthonia, and to Finland. 

 The Ural excursion is timed to take place between 

 July 28 and August 27. There will be a general gather- 

 ing of the party at Moscow on July 29, and those who 

 join are advised to take thick boots, warm clothing, and 

 waterproof cloaks, for there will be rough walking as 

 well as long journeys in open carriages and on horseback. 

 Messrs. Nikitin, Tschernyschew, Arzruni, Karpinsky, 

 and Stuckenberg will act as leaders. The party will 

 take train to Riazan, and thence journeying to Syzran, on 

 the Volga, they will cross Jurassic, Cretaceous, and Ter- 

 tiary strata. Thence from Samara to Oufa, Permian 

 and Triassic rocks will be traversed, while onwards to 

 the Ural mountains the party will pass over Carbon- 

 iferous, Devonian, and Siluro-Cambrian strata, which 

 present evidences of considerable metamorphism, and 

 which, together with various schists, are penetrated by 

 numerous eruptive rocks. The region is famed for its 

 metalliferous deposits, and various mines in rocks bearing 

 gold, copper, and manganese will be visited, as also will 

 be the Imperial stone-cutting works at Ekatherinebourg. 

 The return journey will be made by Perm, Kazan, and 

 Nijni-Novgorod. 



The excursion into Esthonia (August 13 to 27) under the 

 direction of M. Schmidt, will be by rail to Reval on the 

 Gulf of Finland, and then a visit will be paid to the Isle 

 of Dago, when attention will be given to the fossiliferous 

 Upper and Lower Silurian rocks. 



The excursion to Finland will be made under the 

 guidance of M. W. Ramsey. The members will assemble 

 at Helsingfors on August 21, and return to St. Peters- 

 burg on August 28. Tammerfors and Lavia will be 

 reached, and attention will be directed to the glacial 

 phenomena and the various crystalline rocks. 



After the meeting of the Congress is over, the principal 

 excursion will be to the Caucasus, leaving St. Petersburg 

 on September 5, and arriving at Moscow on the following 

 day. The excursion party will then be divided into three 

 sections. A, B, and C. Section A will be conducted by 

 Messrs. Nikitin, Gourow, Tschernyschew, Loutougin, 

 Rouguewitsch, and Konchin. Leaving Moscow, and 

 travelling by Podolsk, the route will be over Jurassic, 

 Carboniferous and Devonian rocks, and on to the 

 Cretaceous strata of Koursk and Kharkow. Thence the 



