463 



NA TURE 



[Sc;t. 7, iSS: 



this decomposition, an observation which appears to destroy ihe 

 usual theories regarding the function of those metallic oxides, 

 which have a similar effect. It was supposed that the action of 

 the catalytic bodies might arise from a power to absorb oxygen, 

 but experiments made by placing black oxide of manganese under 

 conditions similar to those in which it aids the decomposition of 

 potassium chlorate, negatived this supposition. Gas retort 

 carbon can be completely burnt by contact with powdered 

 potassium chlorate at 340°, the action is not attended by fusion, 

 and it appears that in this case chemical affinity determines the 

 decomposition. The action of heat upon potassium chlorate 

 was studied by maintaining it at a constant temperature, and it 

 has been observed that the chlorate begins to give off its 

 oxygen between 330° — 340 , i.e. at temperatures much below its 

 fusing points. This decomposition goes on for several weeks and 

 finally becomes imperceptibly small, but a rise of temperature 

 or the addition of substances known to favour the decomposition, 

 produce a fresh decomposition leading to a further limit. The 

 authors propose a hypothesis to account for this gradual action 

 of heat upon the chlorate. 



SECTION C— Geology 



On the Cause of Elevation and Subsidence of Land, by T. S. 

 Gardner, F.G.S. — The paper claims that the evidence of the 

 permanence of continents is inconclusive as regards eocene and 

 pre-eocene periods, and inquires what the shallower regions of 

 the Atlantic mean, if they do not mean a change of level at the 

 sea-bottom. Assuming with Sir C. Lyell, that at a given depth 

 rocks are molten, and that under further pressure they are re- 

 converted into solids of high specific gravity, the paper demon- 

 strates that the outer envelope is susceptible to and gives way 

 under any increased weight, and recovers when this is removed. 

 The evidence relied upon is that of coral isles, lava-flows, accu- 

 mulations of ice, and of sediment in deltas, estuaries, and along 

 sea-coasts. In these cases, unless there are counteracting agents, 

 subsidence invariably follows, and littoral seas are thus areas of 

 depression. The increasing pressure in deep oceanic basins acting 

 on the fluid layer leads to the elevation of lines of least resistance 

 into ridges or dry-land, these lines generally coinciding with 

 coast-lines, and to volcanic outbursts. Geology demands pre- 

 eocene communication between many lands. The elevation of 

 land continuous between Europe and America in the north, 

 during the Middle Eocene, was coincident with a cessation in 

 the great formation of basalt, and its subsidence with a renewal 

 of this. The conclu-ion is drawn that irregularities of surface 

 have and will continue to become more and more accentuated. 



Notes relating to the Drift Phenomena of Hampshire : (1) 

 Boulders, Ilav/iug Is/and; (2) Chert Debris in the Gravel: 

 (3) Elephant Bed,' Freshwater Gate, by Prof. J. Prestwich, MA., 

 F.R.S., refers to the remarkable boulders of crystalline and 

 other old rocks in P.igham, which were noticed long ago by Air. 

 Dixon, and more recently Mr. Codrington has described similar 

 boulders of Portsea Island, and states that boulders of the same 

 character occur in the gravel of Portsea Island, two boulders of 

 granite, and three of sandstone occurring on the shore near the 

 station, while thirty smaller specimens occurred within a mile 

 westward of the station. Those on the shore facing South 

 Hayling have been collected to form a rockery and local grotto 

 work. The author considers the boulders to have been brought 

 from the Cornwall and Devon coast by floating ice, at the time of 

 the formation of the Brighton raised beach. 



On the Sources of the Salt Supply of India, by Prof. V. Boll, 

 F.R.S., states irrigation in some of the central districts in India 

 has produced sterility, by raising the permanent level of the sub- 

 soil water in the ground, wdiich becomes saline by contact with 

 the lower strata, and through capillary attraction, salts of sodium 

 potassium and magnesia were brought to the, surface. The 

 author states there are five distinct sources of salt in India, 

 the most important of which are wells which have been sunk to 

 a depth of too to 150 feet, and brine obtained, over a large area 

 in the central region of India. In Assam and Burmah saline 

 springs occur in connection with petroleum, 10,000 tons of salt 

 are now being raised fr jm the Samhur Lake. Rock salt occurs 

 of Silurian age, and also in beds of Eocene Tertiary age. 



On the Identification of certain Ancient Diamond Mints m 

 India, by Prof. V. Ball. M.A., F.R.S., F.G.S.— The vague 

 references to India as the only then known source of diamonds 

 by the writers of 2coo years ago, give place to more definite 

 indications of position in Sanscrit works of the sixth century, 



and possibly of sojaewhat earlier dates. In the Baihat Sanita a 

 list of localities is given, but as the stones from some of the 

 localities therein mentioned were copper coloured, it is possible 

 that they were not diamonds. In the Ain-i-Akbari (1590), and 

 also less clearly in the Ferishta's History (1425), a locality named 

 Alheniguras is referred to, which can be identified with Wairu- 

 gurh in the Central Provinces, where the remains of ancient 

 mines are still to be seen. The following localities mentioned 

 by Tavernier (1665), had not been identified until lately, though 

 various attempts had been made by Colonel Rennell and others 

 since his time. Gani or Coulour is Kollnr on the Ivstna : Raol- 

 conda is Ramulkota in Karnul ; Soumelpour was on the Koel 

 river in the Palamow district of Bengal. Kollur would appear 

 from Tavernier's statement to have been the mine where the 

 Great Mogul diamond was found. The same stone is mentioned 

 by Garcias ab Horto, who wrote 100 years before Tavernier. 

 Prof. Ball is of opinion that this stone, which was probably found 

 in the middle of the sixteenth century, was the original of the 

 Koh-i-nur. The author referred to several other early authori- 

 ties, and to the mythical stories which are connected with the 

 accounts of diamond mining, for the origin of which he proposed 

 explanations. 



On the Geology of Cardigan Town, by G. W. Keeping, M.A. 

 — The author considers the Geological Survey in error as to the 

 horizon, on which they place the Silurian rocks, underlying this 

 town. 



Notes on the Bare Valley Beds and Westlcton Beds, by H. B. Wood- 

 ward. F.G.S., considers the introduction r,f the term "Chillesford 

 clay," and its supposed identification with any laminated clay 

 that occurs on any horizon in the Norwich Crag, to have been 

 the source of the confusion at present existing. TLe author finds 

 there is no division between the Bine Valley beds and the 

 Norwich Crag below, and that Messrs. Wood and Harmer are 

 incorrect in referring that the former deposits are Lower Glacial. 



The Iron and Lead Measures of Tynehead, Alston, by Mr. 

 C. E. De Ranee, F.G.S. , of H.M.'s Geological Survey.— 

 The Carboniferous Limestone of this area is split up into a 

 series of limestone separated by thick beds of shale and sand- 

 stone, and traversed by an intrusive sheet of basalt, known as the 

 Whin Sill : the section above that horizon consists only of about 

 200 feet of limestones, while sandstones reach 350 feet, and shales 

 520 feet. Beneath the Whin Sill there are 900 feet of measures, 

 in w hich occur many important beds of limestone, one of which, 

 the Melmerby Scar Limestone, reaches a thickness of 124 feet. 

 The chief lead measures occur in the Great Limestone (70 feet), 

 the Scar Limestone (30 feet), and the Tyne-bottom Limestone. 

 The latter, deriving its mme from its gradual inclination north- 

 ward, forming the floor of the River Tyne ; below this horizon 

 but little has been done in proving the lead lodes in depth, 

 owing to the water-charged condition of the rocks beneath. The 

 veins in nearly every case are faults of small throw, when these 

 traverse limestones, the veins contain lead ; when they pass 

 through sandstones they contain copper, and in both cases the 

 sides consist of valuable deposits of brown haematite, which 

 occasionally reach a thickness of 6 or 7 feet. These at present 

 are not worked, but should a railway be carried up the Tees 

 and into the South Tyne Valley, as is proposed to connect 

 Alston with Middleton in Teesdale, these valuable deposits wit] 

 be available for use in the Middlesboro district. 



/Votes on Alpine Post-Carboniferous (Dyassic) and Triassic 

 Rocks, by the Rev. A. Irving. — This paper is merely sup- 

 plementary to what has recently appeared in the Geological 

 Magazine, on the Dyas and Trias of Europe. Attention is 

 especially drawn to the three following points in connec- 

 tion with the Alpine Dyas (" Permian") :— (1) the occur- 

 rence of the Verrucano, its possible equivalence with the Roth- 

 liegende, as advocated by Giimbel, in opposition to the view of 

 von Hatter, who prefers to regard it as belonging to the lowest 

 horizon of the Trias ; (2) the great volcanic activity manifested 

 in the Alpine area in post -Carboniferous times, as illustrated by 

 the great porphyry district of Bozen (in connection with which 

 the structure of the Ritterer Horn, a "stratified cone," with 

 interbedded "ash" beds and porphyries, is described from 

 recent observations by the author) ; (3) the occurrence of certain 

 Alpine deposits (especially the Bellerophon Limestone of the 

 Puster Thai, and the Grddner Sandstein at Neumarkt near 

 Bozen), which, on palxontologicnl grounds, are regarded by 

 Giimbel as representing a "transition series from the Dyas lo 

 the Trias." Attention is also drawn to the correlation of the 

 Triassic deposits on the northern and southern sides of the great 



