April 22, 1880] 



NATURE 



603 



iron rod had absorbed its maximum of hydrogen (a few minutes 

 after being short-circuited), it became a constant cell, giving but 

 small traces of polarisation when or after being short-circuited 

 for hours at a time. There occur.-, however, a slight diminution 

 of electromotive force after a few day.-.' hard work, being then 

 •52, due to the acidulated water becoming more neutral by the 

 formation of sulphate of zinc and iron. If, however, we wish 

 to restore its full electromotive force, we have only to short- 

 circuit the cell for a few seconds, torrents of hydrogen will be 

 given off, and its electromotive force becomes, on testing of its 

 highest value, '56. 



If we short-circuit the hydrogenised iron cell for one minute, 

 and at once test its electromotive force, we shall find at the 

 first instant a certain amount of polarisation, about 10 per cent., 

 but it rapidly recovers, being at its full initial force in ten seconds' 

 tepoSC ; whilst carbon, platinum, and all other negatives yet 

 tried, did not recover their palari-ation in several minutes' repose. 



Taking the Smee battery as the best example of depolarization 

 in a single liquid, and comparing the constancy of this cell with 

 that of the hydrogenised iron, I find that according to Mr. 

 Latimer Clark's experiment-, in his work on electrical measure- 

 ments, that the electromotive force of a Smee cell is I '017, but 

 when in action only "446. Thus its electromotive force in 

 action is less than that of the iron cell, and its polarisation some 

 five times greater than that of iron, 



I have submitted these results (rather ha.stily obtained) to our 

 president, Mr. VV. II. Preece, and he has kindly consented to 

 have some exact measurements made of the electromotive force of 

 hydrogenised iron, and its comparative freedom from polarisation 

 with all other metals employed as negative elements in a single 

 liquid cell, the results of which quite agree w ith those obtained 

 by myself. 



A practical application of iron as a negative may be mentioned. 

 If we wish to purify mercury from any zinc, or any metal less 

 negative than iron, we have only to place the mercury in dilute 

 sulphuric aciJ, and then introduce an iron rod so that its lower 

 portion shall make contact with the mercury, hydrogen is now 

 freely and constantly given off by the iron, and this c:ntinues 

 until all traces of zinc have disappeared ; and as a proof of this, 

 if after a certain time, when no hydrogen is given off, we simply 

 touch the mercury with zinc for an instant, the hydrogen at once 

 reappears, and continues until this small portion of dissolved 

 zinc has been separated from the mercury. 



In order to render evident the remarkable depolarising power 

 of iron, we use in the same cell several negatives, such as carbon, 

 platinum, silver, copper, and iron ; and if we test these negatives 

 separately for its initial electromotive force, we shall find them 

 all superior to iron. But if we join all the negatives together, and 

 short-circuit the whole with the zinc, iron alone will freely give 

 off its hydrogen, whilst carbon will appear to be entirely inert, 

 and if after this short-circuiting we insultate or separate the 

 different negative-, we shall find on testing them that they are 

 all polarised, carbon being the most so, and iron com) aratively 

 quite free, and at its initial giving the highest electromotive force. 



In conclusion I may add, that if hydrogen seems to be an 

 enemy of iron and steel, rendering it brittle, on the other hand 

 it is perhaps its best friend in rendering it more negative, aud 

 whilst under its entire influence completely preserving it from 

 oxidation or rust. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 



OXFORD. — The debated question of a Natural Science Degree 

 will again come before Congregation on April 27. It is proposed 

 to create a new faculty and to allow students in the Science 

 Faculty to pass a modified form of Responsions and Moderations, 

 in which a modern language may be substituted for Greek, but 

 in which the mathematics required w ill be more advanced than 

 at present. The following is the proposed form of statute : — 



" Of the Faculty of Natural Science. — 1. There shall be a 

 Faculty of Natural Science, in which two degrees shall be 

 granted, viz., the Degree of Bachelor of Natural Science and 

 the Degree of Master of Natural Science. 



" 2. Any person duly matriculated wishing to proceed to a 

 Degree in Natural Science shall be deemed to be a Scholar in 

 the Faculty of Natural Science as well as in the Faculty of 

 Arts." 



In the Natural Science " Respoiisions " candidates shall offer 

 two books, either (1) one Greek and one Latin, or (2) one Greek 



and one German, or (3) one Greek and one French, or (4) one 

 Latin and one German, or (5) one Latin and one French. A 

 special knowledge of the grammar of the languages of the books 

 selected will be required. The candidates will also be examined 

 in arithmetic, in plane geometry, including doc'.rine of similar 

 triangles, and in algebra, including quadratics and ratio and 

 variation. 



In the Natural Science " Moderations " candidates shall offer 

 three books, one being some portion of a Greek or Latin his- 

 torical or philosophical work. The mathematical part of the 

 examination will include theory and use of logarithms, trigono- 

 metry as far as the solution of plane triangles, the rudiments of 

 plane co-urdinate geometry, and the mechanics of solid and fluid 

 bodies treated by elementary methods. 



Atter parsing "Moderations" the student will be at liberty 

 to enter the Natural Science School or the Mathematical School 

 in honours. 



A grant of 75/. has been made from the Worts Travelling 

 Scholars' fund to Mr. J. E. Marr, B. A., of St. John's College, 

 Cambridge, to enable him to travel in Norway, Sweden, and the 

 islands ot the lialtic, and collect evidence and specimens bearing 

 upon the classification of the Cambrian and Silurian rocks, with 

 the understanding that specimens be sent by him to the 

 University, accompanied by reports which may hereafter be 

 published. 



The Qiieen has signed the charter of the "new Royal Irish 

 University, the successor of the Queen's University. The Senate 

 is large and fairly representative. 



SOCIETIES AND ACADEMIES 

 London 



Linnean Society, April 15. — The Rev. G. Henslow in the 

 chair. — The Secretary read a paper for the Rev. R. Boog 

 Watson, on the Mollusca of the Challenger Expedition (Part 5). 

 Some thirty-five species are described and compared, whereof 

 the greater part are new forms and belonging to the families 

 Solenoconchia, Trochida, Risscellida?, Litorinida, and Cerithiidse. 

 The author observes that temperature even more than mere 

 e'epth seems an important condition in molluscan life, while both 

 pjrove barriers to distribution, though great length of time 

 naturally helps escape from these barriers. Where barriers of 

 depth and temperature do not check distribution there is no limit 

 to universality of distribution, and such is the case with certain 

 existing species ; still there is no trace of especial, lasting, and 

 progressive change. — A communication was read by Mr. N. E. 

 Brown on some new Aroidere, with observations on other known 

 forms (Part 1). Of the former the specimens are contained in 

 the Kew Herbarium, and the latter are annotations, chiefly sup- 

 plementary to Prof. Engler's recent monograph of the order. 

 While following Engler, the author has given preference to the 

 classification of Schott. Among others severtl interesting new 

 Bornean forms are described. — Prof. F. Jeffrey Bell next read a 

 note on an abnormal (quadriradiate) specimen of Amblyfneustes 

 formosus, and afterwards Mr. Chas. Stewart exhibited and made 

 remarks on another but differently abnormal specimen of the same 

 species. — Prof. Bell, after a full description of his specimen, ob- 

 serves : that with more or less reason some naturalists have looked 

 on the possession of other than five rays as a character of souk- spe- 

 cific value among the Asterida; and Ophiurida, and have considered 

 that, on account of its greater rarity among the latter, it is of 

 greater value as a mark of distinction ; but such a view must be 

 taken with considerable limitation. The pentamerous arrange- 

 ment of parts in the regular Echinida is, then, only disturbed in 

 one example ; information and specimens are, however, at hand 

 to show how this may have happened. The rarity of any 

 divergence from this five-part division, in face of the numerous 

 variations which occur in the Echinodermata, will doubtless 

 become more and more important as a factor in determining the 

 genealogic.il history of the group. — A series of nut 

 sections of pearls exhibiting many irregularities in structural 

 detail were shown by Dr. J. Murie, and their several peculiarities 

 explained. — Messrs. S. H. Wintle and George liay (of Tas- 

 mania) were elected Fellows of the Society. 



Chemical Society, April 1. — H. E. Roscce, president, in 

 the chair. — The following papers were read: — On betorcinol 

 and some of its derivatives, by J. Stenhouse and C. E. Groves. 

 The authors have extracted from Usnea barbata an acid pro- 

 visionally named barbatic acid, which is probably dimethyl- 



