yune 21, 1883] 



NATURE 



183 



sumed in making the bronze, which consists of 250 kilog. of 

 gold, 8413-5 of tin, 977 of mercury, and 493 of copper. The 

 present image only dates from 1S01. 



\V e have received a German pamphlet by Herr Max Buch, 

 on " Finland and its Nationality Question," being a reprint of 

 papers which have appeared in recent issues of the AuslanJ. In 

 the limited space of seventy-four pages the author gives a short 

 but correct description of Finland, of the prehistoric Finns, 

 according to Ahlquist's researches, of the history of the country, 

 and of the present state of the "national que-tion." He sum- 

 marises the excellent researches by Retzius on the race-characters 

 of the Finns — as far as can be done in a few pages— and dwells 

 upon the recent efforts of Finnish writers towards the develop- 

 ment of the Finnish language and literature as a reaction against 

 the former supremacy of the Swedish language and influence. 

 We notice the interesting fact that although only 7 - 5 per cent, of 

 the Finns can now read and write, and 70 per cent, read, primary 

 instruction has taken during the last few years a great extension. 

 The number of State schools being too limited, they are supple- 

 mented by private instruction. Thus, of the 342,836 children 

 from seven 10 sixteen years old of the Lutheran Finnish popula- 

 tion, only 6983 had not received primary instruction in 1877 

 (1801 of them on account of disease). But only 26,900 

 went to the State schools, whilst 116,201 children received pri- 

 mary instruction in private ambulatory schools, and 177,925 at 

 home. 



The last number of the Izvestia of the Russian Geographical 

 Society contains several interesting papers. M. Veselago gives a 

 sketch of the life and work of the late Count Liitke. Prof. Fr. 

 Schmidt discusses again the claim of Wrangel to the discovery 

 of the land situated north of the Cape Yakan. He tries to 

 prove, against Nordenskjdld, that Wrangel was right in 

 rig the existence of a land which Andiceff said he saw from 

 the li'th island of the Medvyejiy Archipelago; but he did not 

 deny the existence of a land situated north of Cape Yakan. 

 Prof. Schmidt admit-, however, that even with regard lo this 

 land, Wrangel wrote "in different parts of his report with a 

 varying degree of certainty as to the pr bability of its existence." 

 M. Karzin, an official of the Verkhoyansk district, having been 

 struck with the terrible fate of De Long, publishes a most valu- 

 able list of all settlements and places where human beings can 

 be met with at different seasons on the coast of Nop h-Ea tern 

 Siberia. M. Andreeffpu li-hes a brief account of his hydro- 

 graphical researches in the White Sea and o\\ the Murnian coast 

 during the last three year . The flora of the coast becomes very 

 poor north of Archangel. At the Svyatoy Noss lighthouse 

 it consists only of lichens, uios es, and creeping brushes of 

 Betula nana. It improve;, however, west of Kildin and 

 especially we-t of the Ribachiy peninsula, offering excellent 

 forests and meadows at the new colony at Pechenga. The 

 yearly average temperature, which is but — o°'6 CeLius at 

 Archangel, and — 2° ,4 at the Svyatoy Noss lighthouse, reaches 

 - i°i at Kola, and + i°'4 at Vardo. This increase of tempe 

 rature is due, as is known, to the warm current which flows 

 along the coast. Thus, at Svyatoy Noss, during the hottest 

 days, the temperature of water does nit exceed 6° 9 ; and during 

 the autumn it reaches but i°'9. To the west of 30 6' it sud- 

 denly becomes duulile that. In the spring the warm stream- 

 lets reach 4°'3, whilst the cold ones, Bowing close by, reach 

 but I°'9 ; and during the summer the warm streamlets reach I2°'5, 

 whilst the cold ones, close by, reach 6"'9 to 7°'5. It appears thus 

 that one isolated measurement of temperature of water is of little 

 value, the warm current being not so compact along the Murnian 

 coa^t as elsewhere. Under 33° 6' li. long, it leaves the coa-t 

 and flows towards the north-north-east. 'I he positions taken by 

 the warm current at the Murnian coast vary with the seasons, and 

 depend upon the prevailing winds. From April to August it 

 touches the coa-t, but later on it is driven north by the southern 

 winds; in October it already flows off Vardb. Its position 

 varies also for different years, depending upon the prevailing 

 winds. The richness of the fishing depends entirely upon the 

 position taken by the warm current. In 1SS1, the Norwegians, 

 owing to the current flowing in their waters, had the richest 

 prey, whilst in 18S2, the richest prey for a twenty years' series 

 was given by the warm current to the Russian fishers. The 

 same number of the Izvestia contains the first sheets of M. 

 Polakoffs reports on his re.-earches in Sakhalin, and M. 

 Mezhoff's bibliographical index of the Russian geographical 

 literature for the year 1S80. 



M. Thouar, the French traveller, has written a letter from 

 Chili, in which he says that several members of the exploring 

 party under Dr. Jules Crevaux, who was massacred with most of 

 his followers in the early part of la-t year by Indians while 

 making explorations along the Bolivian part of the Pilcomayo, 

 are believed to be still alive, but prisoners in the hands of the 

 Indians. 



THE CAUSE OF EVIDENT MAGNETISM IN 

 IRON, STEEL, AND OTHER MAGNETIC 

 METALS 1 



Neutrality 



'THE apparatus needed for researches upon evident external 

 ■*■ polarity requires no very great skill or thought, but simply 

 an apparatus to measure correctly the force of the evident repul- 

 sion or attraction ; in the case of neutrality, however, the exter- 

 nal polarity disappears, and we consequently require special 

 apparatus, together with the utmost care and reflection in its 

 use. 



From numerous researches previously made by means of the 

 induction balance, the re-ults of which I have already published, 

 I felt convinced that in investigating the cause of magnetism 

 and neutrality I should have in it the aid of the most powerful 

 instrument of research ever brought to hear upon the molecular 

 construction of iron, as indeed of all metals. It neglects all 

 forces which do not produce a change in the molecular struc- 

 ture, and enables us to penetrate at once to the interior of a 

 magnet or piece of iron, observing only its peculiar structure and 

 the change which takes place during magnetisation or apparent 

 neutrality. 



The induction balance is affected by three distinct arrange- 

 ments of molecular structure in iron and steel, by means of 

 which we have apparent external neutrality. 



Fig. I shows several polar directions of the m decides as indi- 

 cated by the arrows. Poisson assumed, as a necessity of his 

 theory, that a molecu'e is spherical, but Dr. Joule's experimental 

 proof of the elongation of iron by i/720,oooth of its length when 

 magneti ed, proves at least that its form is not spherical ; and 

 as I am unable at present to demonstrate my own views as to its 

 exact form, I have simply indicated its polar direction by arrows 

 — the dotted oval lines merely indicating its limits of free elastic 

 rotation. 



In Fig. I, at A, we have neutrality by the mutual attraction of 

 each pair of molecule^, being the shortest path in which they 

 could satisfy their mutual attractions. At B we have the case of 

 superposed magnetism of equal external value, rendering the 

 wire or rid apparently neutral, although a lower series of m de- 

 cides are rotated in the opposite direction to the upper series 

 giving to the rod opposite and equal polarities. At c we have 

 the molecules arranged in a circular chain around the axis of a 

 wire or rod through which an electric current has passed. At D 

 we have the evident polarity induced by the earth's directive in- 

 fluence when a soft iron rod is held in the magnetic meridian. 

 At E we have a longitudinal neutrality produced in the same rod 

 when placed magnetic we-t, the polarity in the latter case being 

 transversal. 



In all these cases we have a perfectly symmetrical arrange- 

 ment, and I have not yet found a single case in well-annealed 

 soft iron in which I could detect a heterogeneous arrangement, 

 as supposed by Ami ere, ' Je ' a Rive, Weber, Wiedermann, and 

 Maxwell. 



We can only study neutrality with perfectly soft Swedish 

 iron. Hard iron and steel retain previous magnetisations, 

 and an apparent external neutrality would in most cases be the 

 superposition of one magnetism upon another of equal external 

 force in the opposite direction, as shown in B, Fig. I. Per- 

 fectly soft iron we can easily free, by vibrations, from the 

 slightest trace of previous magnetism, and study the neutrality 

 produced under varying conditions. 



If we take a flit bar of soft iron, of 30 or more centimetres in 

 length, and hold it vertically (giving while thus held a few tor- 

 sions, vibrations, or, better still, a few slight blows with a 

 wooden mallet, in order to allow its molecules to rotate with 

 perfect freedom), we find its lower end to be of strong north 

 polarity, and its upper end south. On reversing the rod and 

 repeating the vibrations, we find that its lower end has pre- 



1 Paper read before the Society of Telegraph Engineers and of Elec- 

 tricians, on May 24, 1883, .by Prof. D. E. Hughes, F.R.S., Vice-President 

 Continued from p. 162. 



