624 



NA TURE 



{.April 29, i8h6 



respiration. At each expiration the lid sank with the pen. Dr. 

 Gad concluded from his experiments that, by bad ventila- 

 tion of the respiratory centres atitomatic or autochthonous 

 expiration could never be induced, but always inspiration 

 alone. V11. Gad further endeavoured to ascertain what was the 

 limit of deficiency of oxygen and of carbonic acid admixture under 

 which the first traces of dyspnoea shoived themselves, and found 

 that the animals were more sensitive to the excess of carbonic 

 acid than to the deficiency of oxygen. An addition of 3 per 

 cent. CO., was sufficient to excite dyspnoeically augmented 

 inspiration, while they could very well stand an air of 18 per 

 cent, oxygen. The quantities of COj which were mixed with 

 the respiratory air were increased to 26 per cent, without the 

 result being other than increased in.spiration. Regarding the 

 several series of experiments and their results. Dr. Gad would 

 communicate a more special report at a subsequent meeting. 



Meteorological Society, March 2.— Dr. Weinstein spoke 

 on the earth's currents which were observable in the telegraph 

 wires by the disturbances they caused in the message ser- 

 vice, their intensity at times exceeding that of the batteries 

 of eighty Daniell employed for telegraphing. In order to the 

 observation of the earth's currents, two equal metal plates had 

 since the time of Faraday been sunk into the ground and 

 connected by a wire, in which a galvanometer was inter- 

 calated. The deviations of the galvanometer needle might 

 be induced as well by an earth- current as by a current which 

 arose from the contact of the earth-plates with the earth. In 

 the latter case, however, the current would be very weak when 

 the plates were at a great distance from each other. The case 

 being, in point of fact, otherwise, however, the currents in 

 question were accordingly earth-currents. The measurement of 

 them was achieved by means of self- registering apparatus, either 

 in the way of photography in England or mechanically in 

 Germany ; the earth -current was conducted through a coil, 

 that, suspended in the interval between a rod magnet and a 

 hollow cylinder magnet, w.as, under the oscillations of the 

 current, drawn in or pushed out, and, by means of a lever, in- 

 scribed these movements on soot-blackened paper. The direc- 

 tion of the current in the body of the earth was found by obser- 

 vation of two circuits forming a right angle with each other. In 

 Berlin one circuit proceeded eastwards towards Thorn, the other 

 southwards towards Dresden. The observations made in Ber- 

 lin showed a direction of the earth's current from north-east 

 to south-west, while in England the direction went more from 

 north to south with a slight deviation towards the east, and in 

 France a direction from north to south with an inclination 

 towards the west was observed. The earth-current showed a 

 perfectly regular daily variation. In the night the earth-current 

 is slight ; from 8 o'clock in the morning it regularly increases, 

 attains its maximum precisely at 12 noon, thence sinks rapidly 

 till 4 p.m., whence it continues uniformly weak, not to revive 

 till the following morning. A course precisely analogous 

 to that of the earth-current was manifested by the earth's 

 magnetism, the connection of which with the electricity of 

 the earth attracted attention from the very beginning, when 

 disturbances made themselves observable. To demonstrate with 

 perfect precision the coincidence of the two phenomena it was 

 necessary to take for the purpose of comparison not a single earth- 

 magnetic element, but the earth's total magnetism. Thecarth's 

 electricity and the earth's magnetism showed, moreover, in their 

 regular daily course, their affinity, by the simultaneity with which 

 their disturbances occurred. This simultaneity was so precise 

 that in one case the distance between Berlin and Wilhelmshaven 

 could be determined from the time when the disturbance of the 

 earth's current made itself felt in Berlin and the time when the 

 magnetic disturbance occurred in Wilhelmshaven. This simul- 

 taneity of disturbances at distant points of the earth pointed to 

 a cosmical cause. Thus in August last year, at the very time 

 when in Paris the emergence of an altogether unusual solar pro- 

 tuberance was observed, a magnetic disturbance was registered 

 in Petersburg, and a disturbance of the earth's current in Berlin. 

 The earth's current and the earth's magnetism showed further in 

 common the periods of eleven years which coincided with those 

 of the solar spots. In respect of the earth's current, this period 

 could not indeed be demonstrated to a certainty, seeing that the 

 regular observations made respecting it were yet of too recent 

 date ; but the regular course of the oscillations warranted the 

 conclusion of a like period being drawn. A period of from two 

 to five days in which the earth's current and the earth's mag- 

 netism showed in their oscillations alternately larger and 



smaller amplitudes had, in addition, been detected, although 

 the explanation of the phenomenon was not yet forthcoming. 

 With reference to the question which phenomenon was the 

 primary, the earth's current or the earth's magnetism, opposite 

 views were entertained. The earth's electricity was assuredly 

 not strong enough to magnetise the body of the earth ; but, 

 on the other hand, against the assumption that^ the earth's 

 currents were induced by the oscillations of the earth's magnetism 

 an objection might be raised, namely, that in such a case the earth's 

 currents would have to be proportional to the velocities of the 

 oscillations of the earth's magnetism, and not to the oscillations 

 themselves. This question can only be decided by further 

 observations and by experiment. In a wide circle out of telegraph 

 circuits the induction effects of the earth's magnetism might 

 be studied and compared with the earth's currents. The speaker 

 discussed the different theories of the earth's electricity set forth 

 by Faraday, De la Rive, Lamont, Edlund, and the Brothers 

 William and Werner Siemens, without declaring himself de- 

 cidedly in favour of any of them. In conclusion he drew atten- 

 tion to the series of ditferent jerks which showed themselves in 

 the self- registering curve of the earth's currents on the occasion 

 of every thunderstorm. A jerk of this description on the part of 

 the pointer' seemed to correspond with each lightning-flash. 



BOOKS AND PAMPHLETS RECEIVED 



"Memoirs of the Geological Survey of India" : " PalKontologia Indica," 

 Ser xiii. " Salt-Range Fossils, (i.) Productive-Limestone Fossils ; (5) 

 Bryozoa-Annelida.Echinodermata " (with Plates Ixxxvu.-xcvi., by W. 

 Waagen (Truhner).— " Quarterly Journal of the Microscopical Society, 

 .^pril (Churchill).— " Malvern, its Ferns, &c.," by G E. Mackie (J/<i/iw« 

 Aihmliscr).—" Sacred Books of the East," edited by F. Max MuUer, vol. 

 xxvi. " Salapalha Brahmana," part 2, books iii. and iv., by J. Eggeling 

 (Clarendon Press); vols, xxvii., xxviii., "The Li-Ki," by J. Legge.— 

 " .'\nnales de rObservatoire de Moscou," vol. i. part i, 1S86 (Lang, Mos- 

 cou).—" British Fungi," vol.!., by Rev. J. Stevenson (Blackwood).— I'he 

 Naturalist's Diary," by C. Roberts (Sonnenschein). 



CONTENTS P.^GE 



Flowers, Fruits, and Leaves. By Dr. Maxwell T. 



Masters 601 



The Geology of Palestine 601 



A Manual of Chemistry 602 



Our Book Shelf: — 



Winkler's " Technical Gas Analysis " 603 



Roscoe's " Lessons in Elementary Chemistry, Inor- 

 ganic and Organic " ^^Z 



Letters to the Editor : — 



New System of Earthquake Observations in Japan. — 



Seikei Sekiya . . . • ;^ ■ ■ 603 



" The Krakata~o Dust-Glows of 1883-84." — E. 



Douglas Archibald 6o4 



Pumice on the Cornish Coast.— W. Whitaker . . 604 

 Ferocity of Animals.— Dr. George J. Romanes, 



F.R.S 604 



The Climbing Powers of the Hedgehog.— Hyde 



Clarke '^°4 



On the Law of the Resistance of the Air to the 



Motion of Projectiles. By Rev. F, Bashforth . 604 

 Plants Considered in Relation to their Environment 607 



Notes , <'°9 



Geographical Notes ^'^ 



Our Astronomical Column : — 



The Parallax of f'' Auriga: 612 



Astronomical Phenomena for the Week 1886 



May 2-8 ^'3 



On the Forces Concerned in Producing the Solar 

 Diurnal Inequalities of Terrestrial Magnetism. 



By Prof. Balfour Stewart, F.R.S 613 



On the Diurnal Period of Terrestrial Magnetism. 



By Dr. Arthur Schuster, F.R.S 614 



Chemical Affinity and Solution. By W. Durham . 615 

 The Japanese National Survey and its Results . . 617 



University and Educational Intelligence 619 



Scientific Serials 619 



Societies and Academies 620 



Books and Pamphlets Received 624 



