6o6 



NA TURJi 



[AlKIL 27, 1899 



Thi«, with the nriKulnr velocity of ihc earth intluctor, i> all 

 wc need for ilctcrmininj; the nlnolute meaiurc of Ihc rc«i«inncc, 

 ilncc wc know hy cnlculalir>n Ihc coefficient of muliifil induc- 

 tion l)clwccn Ihi- [irirniiry and ncondary nf the IranHfiirniir. 



The mclhiid Iiuh some ftdvanla(;c». The value of ihe carlh'n 

 field need not he connlanl. Thernio-currentii make no differ 

 ence, as we are mini; A.C. vollaRcii, and thciic may he taken 

 very larKC compareil with any |)o!(»il)|e Ihermo-cffcct in the 

 primary. The Bame coils woidd be lined for cielermininK holh 

 the ohm and ampere, ho Ihal any error in calculalinc the co- 

 efiicicnlB for Iheni would affect hoth units. Modificationn will 

 readily !iu(j(;e.Ht thcmRclvcH ; as, for instance, two sets of such 

 coils, one on each arm of a lialance, and the movahle coils 

 BClinu both as secondary and as the movable coil of a Kelvin 

 balance. Kbc.inai.D A. I'Ksskniik.n. 



Western University of Pennsylvania, April 3. 



Fourier's Series. 

 I siioi'i.li like to correct a careless error which I made 

 (Naiiirk, iJcccmber 29, 1898) in descril>in({ the limiting form 

 of Ihc family of curves represented by the c(|uation 



^ = 2 (sin j: - J sin J.r . . . ± - sin «.r) , . . (i) 

 « 



as a r.igzflc; line consisling of alternate inclined and vertical por- 

 tions. The inclined ixirtions were correctly civen, but Ihe 

 vertical portions, whicii arc biscclcd by the axis of X, extend 

 beyond Ihc points where they meet Ihc inclined portions, their 

 total lendlhi bcin^; expressed by four limes the definite inle(;ral 



/" sin // , 

 I " 



If wc call this combination of inclined and vertical lines C, 

 and Ihe ^raph of etpiation (I) C,„ anri if any finite distance </ be 

 specificil, and wc lake for « nnynundier jjreaterlhan 100/r/", the 

 distance of every point in ('„fromC is less than d, and 'he 

 distance of everv point in (J from C„ is also less than <i. We 

 may llicrcforc call C the limit (or limiting form) of Ihe se(jucnce 

 of curves of which C„ is tin- j;encral ilesignalion. 



Hut this limiting form of the graphs of the functions ex|>ressed 

 by Ihe sum (i) is different from the graph of Ihc function ex- 

 pressed by Ihc limit of that sum. In the latter Ihe vertical 

 portions arc wanting, except their miildle points. 



I think this distinction iinpi>rlanl ; for (with exception of what 

 relates lo my unforlunale blunder described above), whatever 

 (lidercnccB of opinion have been expressed on this subject seem 

 due, for Ihe most part, to the fad that some writers have had in 

 mind Ihe limil of Ihe i^afln, and others the /"ra/// of Ihc limil 

 of the sum. A misunderstanding on this point is a natural con- 

 secpicnce of the usage whicli allows us to omit the word limil in 

 certain connections, as when wc speak of the sum of an infinite 

 series. In terms thus abbrcviale<l, cilhir of the things which I 

 have sought to distinguish miiy be called the graph of Ihe sum 

 of Ihe infinite scries. J. Wii.i.AKIi (Jllilis. 



New Haven, .\pril 12. 



Tasmanian Piresticks. 



Willi,!', preparing for a second edition o( the " Aborigines of 

 Tusmania, I received from Mr. (as. Hackhouse Walker, of 

 llobart, two separate Bcc<ainlsof (ircmaking by the aborigines, 

 which differ materially from those already known. The accounts 

 come from two very old colonists, Mr. Uayner and Mr. Cotton, 

 anil describe fire as being obtained by means of the stick and 

 groove process. Mr. Kayner's account runs thus : "A piece of 

 llal wooil was obtained, and n groove was made the hill length 

 in Ihc centre. Another piece of wooij about afoot in length, 

 with a point like a blunt chisel, was worked with nearly light- 

 ning rapidity up and ilown the groove till it caught in a flume. 

 As soon as the slick caught in a blare, a piece of^burnl fungus, 

 or punk, as it is generally termed, was applieil, which w<«ild 

 keep alight. I cannot say what kind of wood it was. ,My 

 father has seen them light it. The piece with the groove, he 

 said, was hard, the other soft. The bliirks in Australia get 

 fire by the same method. I have seen Ihul done. I think it 

 almost impossible for a white man 10 do it, for I have seen it 

 tried, and always prove a failure." Cottim's account agrees in 

 Ihe main with Kayner's. We arc thus in pi>ssc»siim of accounts 

 of three distinct methods of fire production, vii:. : (1) flint and 



NO. 1539, VOL. 59] 



tinder; (2) fire drill nnd Docket ; (3) stick and groove. At fimt 

 sight ll may appear incredible that a race so low in culture could 

 have known and used there methods; nevertheless such a sup- 

 position might occur, for some neighbouring irilies in Australia 

 are known to have al least two methods. As regards the Tas- 

 manians, we may, I think, leave out of consideration the flint 

 process, as both I'urneaux and I^i Ilillardierc seem lo have mis- 

 taken so-called Hint implements for fire flints. We m.iy also 

 eliminate indefinite accounts which simply refer lo the process 

 used as one of rubbing two .slicks logelher, although rubbing 

 describes rather Ihe slick and -groove methoil than Ihe drill 

 process. We may also omit the statement alKiul the fire-drill sup- 

 plied by Homirck's bushranger as being unlruslworlhy. We are 

 thus left with Ihc two specimens of fire-drill 'in Ihe I'itt-Kivers 

 Museum, Oxford, and in the possession of .Sir John Lubbfjck, 

 respectively) supplicil by Dr Milligan and I'rotcclor Robinson, 

 wilh Melville's (lescriplion and with A. M. l)avies' description. 

 When Melville published his V. D. Almanac in 1833, he gave 

 a short account of Ihe aborigines, but to fire-making he made 

 no reference at all ; when he wrote his " rresent State of 

 Australia" (mostly' an account of Ta<maniaj, printed in Iy<mdon 

 in 1850, he described the drill method of making fire as having 

 been used by the Tasinanians. But, in Ihe me.inwhilc, Davies, 

 writing in 1S45 in the 7'fliw. Joiirii. of Sd., says he is "in- 

 formed" that Ihe Tasmanians raised fire by the drill process. 

 Hut this statement, on hearsay, was madi- long after the 

 aborigines had been deported to Flinders Isl.-ind (1837), and 

 after they had long been familiar wilh Australian aborigines im- 

 ported into Tasmania ; so that, although his statements may in 

 general be relied on, this one wants confirmatory support, 

 especially as his statement is the first one describing the drill 

 process as being a Tasmanian method. Melville's .account ap- 

 pears to me lo be taken from Davie.s. Milligan knew nothing 

 of Ihc alH>rigines until 1S47, when he was put in charge of them 

 al Oyster Cove after their return from Minders Island, and al 

 a lime when it was not likely lhal, in close proximity to j 

 Kuropean settlements, they wcudd have continued to produce fire I 

 by native methods. Althiaigh we are much imlebted to Milligan * 

 fi)r the vocabularies, on the other hand there is considerable 

 carelessness in his Iranslaliim of the native sentences, and 

 it is well known locally he was not interested in his 

 charge, llencc his presentation to liarnard Davies of a fire J 

 drill as a Tasmanian instrument does not prove Ihe drill to I 

 have been Tasmanian. Uobinson, in spile of his intimate ] 

 intercourse wilh Ihe aborigines, and his voluminous reports on 

 his doings while capturing Ihc wretched remnants, has left u.h 

 such a comparatively small amount of inforination concerning 

 them, that I have for a hmg lime past come in the conclusion I 

 that he was a very umdiservant man, an opinion largely con- I 

 firineil by his presenlaliim lo Harnard liavics of ground I 

 Australian stone imiilemenls as Tasmanian, but the real origin I 

 of which was sellled as Australian by Prof. Tylor's paper im the I 

 .subject read at the Oxford meeting of the Itrilish Association. I 

 As Kobinson was afterwards Protector of Aborigines in Victoria, ' 

 it is not at all unlikely that he confused his specimens, and called 

 them Tasmanian inslead of Australian. On the other hand, we 

 have circumslanlial accounts of stick and groove fire-making 

 apparatus by two seillcrs, well ailvanceil in years, who carry us 

 back to Ihe early part of the century when the natives were still 

 roaming al«iul ihe country before they were wholly robbed ol 

 it, and lo a lime when they had been little in louch with 

 Australians or Europeans. K.ilher there were two methods of 

 fire-production used by the natives, or the slick and groove was 

 the <mly one. II. LiNc Uorit. 



Halifax, Kngland, April 13. 



WIRELESS TELEGRAPHY. 



A I,'ril( )1 T.II ,-it the present moment there is not a 

 ■^*- single lommercial line of Ihc so r.illcd wireless 

 telegraphy ,il woik, and pinhahly not .-i single penny has 

 yet been earned by those exploiting it, the ortc pound 

 shares of the ( umpany have been (|iiole(l at six pounds, 

 and perh.ips mine. .\t the same time Ihe shares of many 

 of the .Subm.innc I'able Companies have fallen ronsiiler- 

 ably owing to the popular delusion that wireless tele- 

 graphy is goiii)4 to displ;iic wires. Thus .1 popular scare 

 — the outcome of ignorance has appie<iated the one 

 property and ihprccialed the other to the value of about 



