'50 



NA TURE 



[June 15, 189;: 



Mr. H. O. Forbes's Discoveries in the Chatham Islands. 



Referring to ray former note (sufra, p. loi) I cannot find 

 that I have been guilty of even " a slight confusion of dates," as 

 Mr. Forbes says (i/i/ra, p. 126). On his last visit to Cambridge 

 he told me he had forgotten the name I had before written, 

 and asked me to renew my suggestion. I thank him fjr the kind 

 terms in which he speaks of me, but I must be allowed to dis- 

 claim the opinion " that the Chatham Island form was nearer to 

 Aphanapteryx than the latter was to Erythromachus." 



Alfred Newton. 



Magdalene College, Cambridge, June 10. 



Linnean Society Procedure. 



At the anniversary meeting of the Linnean Society complaint 

 was made that the attendances at the evening meetings were 

 greatly falling off, and fellows were urged to remedy this. The 

 bad attendance is, I think, largely attributable to the lamentably 

 unbusinesslike routine into which the Society's proceedings have 

 fallen, and is not likely to be remedied until thai is first reme- 

 died. Permit me to indicate what appear to me four primary 

 defects i;i the Society's proceedings. 



(1) The actual scientific business of the evening is frequently 

 dispjsed of in an hour; so that fellows, who attend, sacrifice 

 their evening for very inadequate reward. 



(2) In the agenda no intimation is given as to whether the 

 papers to he read will be really read hy \.\\&\x authors, or whether 

 merely a few sentences will be rattled through by the secretary 

 in order that the paper can be marked as " read. " It may thus 

 happen that fellows who attend specially to hear some particular 



' paper read and discussed get nothing for their pains. For 

 instance, a short lime since, some of us came up specially to 

 hear a paper by Dr. Plowright on the Aeeidiomycetcs, but 

 instead of being treated to a biological paper, followed by a dis- 

 cussion, all that we heard was a few sentences from the introduc- 

 tion read by the secretary ! Naturally this sort of thing militates 

 against regular attendances. 



(3) Even when an important paper is intended to be read, it 

 may not be reached at all, or if reached may be hurried over 

 and not discussed for want of lime. VVliy is this? Simply 

 because the Society allows "exhibitions" to be intercalated 

 between the formal business and the papers. These exhibitions 

 are often of much interest, often, again, very trivial, but anyhow 

 are quite secondary in importance to the papers, and clearly 

 should be deferred until the papershawe been disposed of, instead 

 of taking precedence. These exhibitions are not advertised in 

 the diaries of Societies ; and it is rather hard that fellows, «ho 

 have attended to hear an important paper on some new dis- 

 covery, should go away disippointed because some incon- 

 siderate visitor possibly is allowed to prose about a trifling 

 exhibition for half an hour ! 



(4) A very grave defect is the confusion of heterogeneous sub- 

 jects in one evening. If, for instance, alternate meetings were 

 devoted entirely to botanical and zoological papers respectively, 

 probably the attendances would be increased ; but the botanists 

 cannot be expected to display much interest in a new genus of 

 earthworms, nor the zoologists in a monograph of Dianthus. 



If the Council could see their way to adopting these simple 

 reforms that I have suggested, I believe that the attendances 

 would be much increased. F. H. P. C. 



THE GERMAN MATHEMATICAL 

 ASSOC I A TION} 



"ymS is the Catalogue of the Exhibition that was to 

 •*■ have been held last year in the picturesque old 

 town of Niirnberg ; but in consequence of the state of 

 health in Germany, the meeting of the German Mathe- 

 matical Association and the exhibition were postponed ; 

 and they are now to be carried out this year at Munich, 

 in the month of September. 



The last exhibition of a similar kind was that held 

 in London in 1876, the cal:alogue of which shows 

 that a large collection of apparatus, much of it of a great 

 historical interest, was brought together. 



1 "C.italogue of \fathematical and Mathematico- physical Models, Appar- 

 atus, and Instruments." Edited, in conjunction witli numerous colleagues, 

 by Waliher Dyck. Munich, 189a. 



NO. 1233, VOL. 48] 



In the present collection the objects of historical in- 

 terest are comparatively few in number ; but, on the 

 other hand, the various models and apparatus intended 

 to illustrate mathematical principles and ideas show 

 what great advances have been made in this branch, so 

 much neglected in our own country. 



Prof. Armstrong has recently described in these 

 columns the superiority of the systematic manner in 

 which chemical science is carried out in Germany ; and 

 the present Catalogue will show how much we have to 

 learn in the principles of object teaching and illustration 

 in Mathematics. 



The Catalogue is divided into two parts. The first 

 part consists of a collection of short and interesting 

 articles. 



I. " Geometrical enumeration of the real roots of 

 algebraical equations," by F. Klein, in connection with 

 which No. 47, the plaster model of Sylvester's Amphi- 

 genous Surface (constructed by Prof. Henrici) for show- 

 ing the relations for a quintic equation, may be con- 

 sidered. 



II. "Equidistant curve-systems on surfaces," by A. 

 Voss. 



III. "Elementary discrimination of singularities of 

 algebraical curves," by A Brill ; illustrated by instruc- 

 tive diagrams. 



IV. " On the constructive postulates of geometry ot 

 space, in their relation to the methods of descriptive 

 geometry," by G. Hauck ; an article of great interest to 

 students of Euclid's axioms, and of their modern develop- 

 ments. 



V. " Historical studies on the organic description of 

 plane curves, from the earliest times to the end of the 

 eighteenth century," by A. v. Braunmiihl ; in this article 

 the mechanical methods of the construction of curves, 

 which are perpetually being re-invented, are traced back 

 to their original sources, with interesting historical re- 

 ference?. 



VI. " On the methods of theoretical Physics," by L. 

 Boltzmann, is a humorous article, describing the fori ler 

 antiquated methods of teaching Natural Philosophy in 

 Germany, apparently not very different to what man) of 

 us remember in this country, until Maxwell's vivifying 

 influence made itself felt. 



Prof. Boltzmann gives with wonderful clearness 

 Maxwell's ideas about the use of models in Physics ; 

 contrasting the views introduced by him with those 

 held before. This article of Prof. Boltzmann is in 

 course of translation and publication by the Physical 

 Society. 



VII. "Mechanical integration," by A. Amsler ; this 

 gives a complete account of the theoretical principles 

 which underlie the action of Planimeters ; it is illustrated 

 with carefully-drawn diagrams. 



VIII. "Instruments for Harmonic Analysis," by O. 

 Henrici. 



The Catalogue proper begins with the second part ; 

 this again is divided into three sections. 



The first section contains instruments relating to Arith- 

 metic, Algebra,TheoryofFunctions,and Integral Calculus, 

 such as Arithmometers,of which the collection and illustra- 

 tions appear very complete ; Gallon's Ouicunx, illustrating 

 the laws of probability of error; instruments for the solution 

 of equations, Galton's Trace-computer, models of Rie- 

 mann sheets by Prof. Schwarz, of functions of a complex 

 variable by Prof. Dyck, and a very complete and pro- 

 fusely illustrated collection of Planimeters and Harmonic 

 Analysers of all descriptions. The Kev. F. Bashforth's 

 pioneering description of a Harmonic Analyser, read 

 before the British Association in 1845, deserves especial 

 attention. The elegant little planimeter of Messrs. Hiiie 

 and Robertson, of New York, might well find a place in 

 the exhibition. In this instrument the record of area is 

 made by the sidelong movement of a sharp-edged wheel 



