Oct. 2, 1884] 



NA TORE 



553 



Dr. Stephen Macadam. — For the last fourteen years the author 

 has devoted much attention to the illuminating values of dif- 

 ferent qualities of paraffin oils in various lamps, and to the pro- 

 duction of permanent illuminating gas from paraffin oils. The 

 earlier experiments were directed to the employment of paraffin 

 oils as oils, and the results proved the superiority of the paraffin 

 oils over vegetable and animal oils, especially for lighthouse 

 service. The later trials were mainly concerned with the break- 

 ing up of the paraffin oils into permanent illuminating gas, and 

 the results formed the basis on which paraffin oil gas has been 

 introduced into the lighthouse service of Great Britain, both for 

 illuminating purposes and as fuel for driving engines of fog- 

 horns. The following table shows the results of his investiga- 

 tions on the relative values of the crude, green, and blue oils : — 



Crude Green Blue 



Gas per gallon in cubic feet ... 98 ... 102 ... 127 



Candle power 50 ... 53 ... 54 



Light value of gas from ton of oil 



given in lbs. of sperm candles 4494 ... 4741 ... 6044 

 On the Assimilation of Atmospheric Nitrogen by Plants, by 

 W. O. Atwater. — It is almost a universal opinion that free 

 nitrogen is not assimilated by plants. He referred to the classic 

 experiments of Boussingault and Lawes, of Gilbert and Pugh, 

 which, commonly regarded as decisive, may have been performed 

 without consideration to certain conditions. Experiments made 

 by the author show that at any rate certain plants grown under 

 normal conditions do assimilate nitrogen. Peas were grown in sand 

 which had been purified by burning and washing, and to which 

 weiv applied nutritive solutions containing known quantities of 

 nitrogen. The amount of nitrogen supplied to the plant plus 

 the amount contained in the seed was compared after the ex- 

 periment with the amount given by analysis of the plant and 

 the residual solution. The excess of the latter amount over the 

 former, which in some cases was excessive, represented the 

 nitrogen acquired from the air. 



Prof. Gilbert dissented from the conclusion drawn by Prof. 

 Atwater, as he had found that, the greater the care used to 

 prevent foreign matters accumulating on the plants under ex- 

 periment, the less nitrogen was found in excess of that obtained 

 from the seed and soil. 



Prof. Frankland communicated the results of a study of the 

 phenomena attending the discharge of accumulator-cells contain- 

 ing alternate plates of lead peroxide and spongy lead : (1) The 

 energy of a charged storage-cell is delivered in two separate 

 portions, one having an E.M.F. of 2 volts and upwards, the 

 other an E.M.F. ofo'5 volt and under. One of these may be 

 conveniently termed useful, and the other useless, electricity. 

 (2) The proportion of useful electricity obtainable is greatest when 

 the cell is discharged intermittently, and least when the dis- 

 charge is continuous. (3) Neither in the intermittent nor con- 

 tinuous discharge at high E.M.F. is the current, through uni- 

 form resistance, augmented by rest. At low E.M.F., however, 

 the current, after continuous discharge of the high E.M.F. 

 portion, is greatly augmented, but only for a few minutes. This 

 augmentation of current at low E.M.F. after rest is hardly per- 

 ceptible when the high E.M.F. discharge has been taken inter- 

 mittently. (4) The suddenness of fall in potential indicates two 

 entirely distinct chemical changes, the one resulting in an 

 E.M.F. of about 2-5 volts, the other in one of about 0-3 volt. 



(5) The chemical change producing low electromotive force is the 

 first to occur in charging, and the last to take place in discharg- 

 ing, the cell. It is the change which occurs during what is 

 called the "formation" of a cell, and, for economy's sake, a 

 reversal of this change should never be allowed to take place. 



(6) Currents of enormous strength can be readily obtained from 

 storage batteries coupled up in parallel, viz. a current of 

 25,000 amperes from only 100 cells. Such a current reduces to 

 insignificance the output of the large-t dynamo ever built. It 

 is to be hoped that currents of this magnitude will open up new 

 probabilities of research into the constitution of matter. 



SECTION C— Geology 



Plan for the Subject-Bibliography of North American Geology, 

 by G. K. Gilbert, of the U.S. Geological Survey.— The 

 United States Geological Survey is engaged on a Bibliography 

 of North American Geology. The work when completed will 

 give the title of each paper with the title-page of the containing 



book, and the number of plates, the whole being arranged alpha- 

 betically by authors. There is in contemplation also the simul- 

 taneous preparation of a numbei of more restricted bibliographies, 

 each covering a division of geologic literature. The plan 

 includes abbreviated titles of papers with reference to the pages 

 on which the special subjects are treated, the entries in each 

 bibliography being arranged alphabetically by authors. The 

 selection of topics for treatment in this manner involves the 

 classification of geologic science, and Mr. Gilbert submitted a 

 tentative classification requesting the criticism of geologists. 



Marginal Kanus, by H. Carvill Lewis, A.M., Professor of 

 Geology at Haverford College. — After reviewing the work on 

 American kames, and the theories of the origin of kames, the 

 author describes his investigations of short kames at the extreme 

 margin of the ice-sheet along the line of the terminal moraine in 

 Pennsylvania. These marginal kames run backwards from the 

 edge, of the ice, draining it by a sub-glacial drainage. These 

 kames are discussed in detail, and are thought to represent sub- 

 glacial rivers formed during the melting of the ice-sheet. 



On the Geology of South Africa, by T. Rupert Jones, F.R.S., 

 F.G.S., &c. — The contour of the south coast is parallel with the 

 outcrop of the strata in the interior, from Oliphant's River 

 (31° 40' S. lat.) on the west coast, southward to the Cape, and 

 then eastward to about 33° 30' S. lat. Here the edges of the 

 strata, formerly bending round to the north, have been swept 

 away to a great extent ; but their outcrop is again seen on the 

 east coast at St. John's River (31° 40' S. lat.), where they strike 

 north-eastwardly through Natal, probably far up the country. 

 (1) Gneissic rock and the Namaqualand Schists apparently under- 

 lie the others, coming out on the north west, and exposing a 

 narrow strip on the south coast. (2) Mica Schists and Slates, 

 interrupted by Granites here and there, form a curved maritime 

 band, from about 30 to 70 miles broad, and are known as the 

 Malmesbury Beds (Dunn). These and the beds next in succes- 

 sion (the Bokkeveld Beds, 3) are overlain unconformably by the 

 Table-Mountain Sandstone (4), 4000 (?) feet thick, which forms 

 patches and extensive ridges, and possibly dips over No. 3, to 

 join No. 5, the Witteberg Beds. Nos. 3 and 5, together about 

 2100 feet thick, lie parallel, and form a concentric inner band. 

 The former contains Devonian fossils ; the latter is probably of 

 Carboniferous Age (with Lepidodendron, &c. ), and forms the 

 Wittebergen and Zwartebergen in the Cape District, and the 

 Zuurbergen in Eastern Province. The Ecca Beds (6) come 

 next ; Lower Series, 800 feet ; Conglomerate Beds (Dwyka), 

 500 feet ; Upper Series, 2700 feet ; conformable with No. 5 ; in 

 the south much folded, and in undulations throughout, until it 

 passes under the next set of beds, No. 7, in some places 50 miles 

 to the north. The Ecca Beds have fossil wood and plant remains 

 in abundance here and there, but these have not been clearly 

 determined. This series has not been well defined until lately, 

 and even now its limits are not fully determined. It includes 

 the Karoo Desert, and therefore takes in the lowest members of 

 Bain's great Karoo Formation, Nos. 12 and 14 of his map (1856), 

 or the Ecca, Koonap, and part of the Beaufort Beds of fones 

 (1867). The series No. 7, horizontal and unconformable on the 

 Ecca Beds at the Camdeboo and elsewhere, retains the name of 

 Karoo Sandstones : and after a width of about 40 miles is con- 

 formably surmounted by a set of somewhat similar beds (8) in 

 the Stormberg ; and thus No. 7 should be regarded as the Lower, 

 and No. 8 the Upper, Karoo Sandstones. The latter end off 

 northwards in the Draakensberg, Natal, Orange Free State, the 

 Transvaal, and Zululand, with the still horizontal Cave Sand- 

 stone and associated beds. The Lower Karoo Sandstones 

 probably thin away northwards beneath the others. Below the 

 Karoo Sandstones, and dying out southwards near the Camde- 

 boo (Prof. Green), are the Shales (7*), which constitute the 

 country around Kimberley, described as the Olive Shales of the 

 Karoo Formation by G. W. Stow. These die out northward 

 against the old rocks of Griqualand-West and the Transvaal. 

 Tiny contain Glacial Conglomerates in their lowest (earliest) 

 beds, in Griqualand-West, just as the Ecca series has its great 

 Glacial Conglomerate (the Dwyka Conglomerate in No. 6) in its 

 lowest portion. As the Stormberg Beds (8) lie upon the Olive 

 or Kimberley Shales (7*) in the Orange Free State, the Lower 

 Karoo Sandstones (7) must die out northwards. The Kimberley 

 Shales contain some Reptilian bones and plant remains, and 

 some coal on the Vaal ; the Karoo Sandstones are rich with 

 Dicynodont and other Reptilian bones, and have some Fish 

 remains ; and their upper portion (Stormberg) contains Ferns 

 ami Cycadeous leaves, and some seams of coal. A fossil mammal 

 also has been found in this series. Throughout its range the 



