82 



NATURE 



[May 1 6, 1878 



Challenoer's officers ^ at Valparaiso and Monte Video, compared 

 with those made by preceding observers, show that within half 

 a century the whole force had respectively diminished one-sixth 

 and one-seventh— at the Falkland Islands one-ninth. Farther 

 north we find at Bahia and Ascension Island, in the same period 

 of time, an equally marked diminution of one-ninth of the force. 

 This area of diminishing force has wide limits ; it would appear 

 to reach the equator and to aproach Tahiti on the west and St. 

 Helena on the east ; at the Cape of Good Hope there is evidence 

 of the force increasing. 



" Such are the facts, and how are we to interpret them ? Which- 

 ever way we look at the subject of the earth's magnetism and its 

 secular changes, we find marvellous complexity and mystery ; 

 lapse of time and increase of knowledge appear to have thrown 

 us farther and farther back in the solution. The terella of 

 Ilalley, the revolving poles of Ilansteen, and the more recent 

 hypotheses of the ablest men of the day, all fail to solve the 

 mystery. We must not, however, be discouraged at these 

 repulses in the great conflict for the advancement of human 

 knowledge. The present century has been productive of keen 

 explorers in the field of terrestrial magnetism ; others emulous 

 of fame are pressing rapidly from the rear, and knowing as we 

 do that knowledge shall be increased, we may confidently anti- 

 cipate the day when this, one of Nature's most formidable 

 secrets, shall be revealed." 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 



At the annual meeting of the Convocation of the University 

 of London on May 14, a report from the annual committee was 

 presented which recommended closer union and co-operation of 

 the colleges and medical schools affiliated to the University with 

 each other and with the Senate, and also more direct participation 

 by the University in the work of higher education and in the 

 encouragement of mature original work. The following reso- 

 lutions were carried by large majorities after an animated 

 debate, in which Drs. Odling, Payne, Baxter, Pye-Smith, and 

 Weymouth, and Messrs. Ilutton, Carey Foster, R. N. Fowler, 

 and Fitch, took part: — i. That while Convocation recognises 

 the advantages of examinations conducted by a body independent 

 of the teachers of the caiididates for degrees, it is expedient that 

 the course of study pursued in those institutions should be 

 brought into closer connection with the Senate. 2. That with 

 this object it is desirable for the Senate to exercise its power 

 under the present Charter of revising the list of affiliated Col- 

 leges, and from time to time of admitting to or excluding from 

 this list according to the position taken by these Colleges at the 

 University examinations for degrees, and on such other grounds 

 as the Senate may in each case determine. 3. That it would be 

 desirable that the educating bodies included in the revised list 

 should be invited to communicate, by delegates or in writing, 

 with the Senate, and that facilities should be afforded to such 

 delegates of deliberating together and of communicating with 

 the Senate, especially on the subject of examinations. 4. That 

 it is desirable for the examiners of the University, either in 

 faculties or collectively, to form a Board, one of whose functions 

 would be to consider and report upon any subject connected 

 with the examinations which they might deem of importance to 

 the University. 5. That it is desirable that the University 

 should take advantage of such opportunities as may present them- 

 selves of promoting, by the institution of University chairs, or 

 otherwise, the cultivation of such higher or less usual branches 

 of study as can be more conveniently or more efficiently taught 

 by a central body. 6. That it is desirable for the Senate to 

 consider the importance of recognising independent research in 

 the examinations for the higher degrees in such way as the 

 senate may approve. 



'.'■ M. Bardoux has sent to the French Chamber of Deputies a 

 project for establishing in Algiers ecoles preparatoires of science, 

 letters, and law, in order to organise in the colony superior 

 teaching. The expenses are estimated at one-and-a-half million 

 of francs. An ecole preparatoire of medicine was established 

 eighteen years ago. 



The late Prof. Wilhelm Piitz, well known through his excel- 

 lent geographical and historical hand-books, has bequeathed the 



' This extended and carefully made series are prepared for publication ; 

 we cannot too highly estimate this valuable contribution to magnst'cal 

 scieace. 



sum of 115,000 reichsmark (5,7So/.) to the University of Bonn, 

 with the stipulation that it is to be employed for furthering the 

 caching of geography and history. 



SCIENTIFIC SERIALS 



American Journal of Science and Arts, April. — In this 

 number Prof. Hastings records observations which prove that 

 the variation in dispersive power of glass, attending variation in 

 temperature, is relatively enormously greater than that in the 

 refractive power. This could hardly have before escaped notice, 

 but for a singular relation in the co-efficients, in virtue of which, 

 probably, an achromatic combination for one temperature is good 

 for all others within moderate limits. — Prof. Rowland has made 

 a new determination of the absolute unit of electrical resistance, 

 his method being to induce a current in a closed circuit by re- 

 versal of the main current. He finds the B.A. unit too great by 

 about '88 per cent. A difference of nearly 3 per cent, between 

 his result and that of Kohlrausch he endeavours to explain from 

 a criticism of the latter's method, pointing out what he thinks its 

 defects. — Prof. Langley differs from M. Janssen as to the ultimate 

 form of the "grains " in the solar photosphere, regarding them as 

 the ends of filaments (a simile he employs is that of a bird's-eye view 

 of a field of grain acted on by wind), whilst M. Janssen thinks 

 them literal spheres. — In the projection of microscope photo- 

 graphs. Prof. Draper increases the brilliancy of the result by 

 removing the supporting stage of the slide further from the 

 condenser so that a convergent beam of light may fall on the 

 object. — Several papers in this number deal with points in 

 American geology and physiography ; the surface geology of 

 South- West Pennsylvania, the drif tless interior of North America, 

 the ancient outlet of the Great Salt Lake, Lower Silurian fossils 

 in Pennsylvanian limestone, intrusive nature of the triassic trap- ■ 

 sheets of New Jersey, &c. A tree-like fossil plant, Glypto- 

 dendron, lately found in the Upper Silurian rocks of Ohio is 

 described by Prof. Claypole as (from its position) possessing a 

 peculiar interest. 



Annalen der Physik und Chemie, No. 3, 1878.— -M. Rontgen 

 here describes experiments which seem to invalidate results 

 obtained by Wilhelmy in 1863 and 1864 regarding the condensa- 

 tion of fluids on the surface of solid bodies. He finds the differ- 

 ence of the two surface tensions, caoutchouc-air and caoutchouc- 

 water, to be about 8'o mg. per millimetre, when both have 

 attained their normal value (which does not occur immediately 

 after contact). — It is shown by M. Claes that for extremely 

 dilute solutions of a substance with absorption -bands, the posi- 

 tion of these bands may considerably vary, and a band is abso- 

 lutely characterised by that wave-length which belongs to it in 

 solution in solvents that are without dispersion. — In a paper on 

 quantitative spectrum analysis, M. Vierordt investigates the influ- 

 ence of narrowing of the entrance-slit on colour-tone and bright- 

 ness ; by adapting four movable plates to the slit he has been 

 able accurately to fix the amount of error in his determinations 

 of intensity of light with his spectral photometer, and show that 

 throughout the spectrum they are very small, and may mostly be 

 neglected. In every case, however, they can be fully corrected 

 by arrangements he describes. — M. Lommel advances a theory 

 of normal and anomalous dispersion, and M. Frohlich applies 

 the principle of conservation of energy to the phenomena of dif- 

 fraction. — The temperature-surface of water vapour is treated by 

 M. Ritter. 



SOCIETIES AND ACADEMIES 

 London 



Royal Society, April 4. — "On the Determination of the 

 Constants of the Cup Anemometer by Experiments with a 

 Whiriing Machine," by T. R. Robinson, D.D., F.R.S. 



In his description of the cup anemometer {Trans. R. I. 

 Academy, vol. xxii.). Dr. Robinson had inferred from experiments 

 on a very limited scale with Robins whirling machine that the 

 limiting ratio of the wind's velocity to that of the centres of the 

 cups = 3. Recent experiments by M. Dohrandt have shown 

 that this number is too great. As some of the details of M. 

 Dohrandt's experiments appeared objectionable, and as all the data 

 necessary for determining the constants were not given, it seemed 

 desirable to repeat them. 



