Philosophical Institute of Canterbury. 45 



recent work of Thomson, Lenard, Lorenz,, and others, showing how these scientists 

 have been able to establish the existence of negatively charged electrons in matter. 

 The mass of these electrons has been found to have an exceeiUngly small value, 

 being in fact only one-thousandth part of the hydrogen atom, which we had hitherto 

 supposed to be the smallest part of matter capable of separate existence. Moreover, 

 research has led to the interesting discovery that this mass is not mechanical, but 

 electric in origin, and is really due to the rapid motion of a charge of electricity. 

 Thomson has thus been led to put forwaid the tentative view that all matter is 

 electric in origin, the atoms of all elements containing these negatively charged 

 electix)ns in rapid rotation inside a positively charged sphere. These electrons are 

 diffei-ently arranged in the atoms of the different elements, but the arrangement is 

 always the same in the atoms of the same element. On this supposition it is 

 pt>ssible to give a real meaning to the periodic table of the chemist : for a periodic 

 arrangement of the electrons would necessarily lead to a periodic recurrence of 

 many chemical and physical pi-operties. 



In conclusion, the' lecturer quoted from the presidential address of Professor 

 Sir J. .J. Thomson to the British Association last year, wherein he expressed the 

 opinion that the experimental work of the last decade had given new life to 

 physics, but that many a difficult peak must yet be scaled before an outlook over 

 the whole constitution of matter and of the imiverse can be hoped for. 



At the oouclusion a hearty vote of thanks was accorded to Dr. 

 Denhain for his address. 



Sevkxth Mektctg : -jfh October^ 1910. 



Present: Mr. R. M. Laing (President), in the chair, and fifty-five 

 others. 



Xtw Jlember.^.—}ir. J. A. Pannett and Dr. C. Morton Auderson. 



Letter from Dr. W . S. Brucf. — A letter was received from Dr. W. S. 

 Bruce acknowledging the receipt of a copy of the " Snbantarctic Islands 

 of Xew Zealand," and eougratiilatiug the Instittite on its production. 



Hocken Memorial Fund. — The President dreAv the attention of mem- 

 bers of the Institute to the Hocken Memorial Fund. 



Paper.$. — 1. "Note on the Flora of Mount Egm<''^ Correction," 



by Di . L. Cockayne (see p. 49). 



2. "'Additions to the Fish Fauna of New Zealand: Part II," by 

 Edgar R. Waite (see p. 49). 



3. A Preliminary Phytogeographical Sketch of the Vegetation of 

 the Mount Arrowsmith District." by Dr. L. Cookayne and R. M. Laing. 



The paper deals in the first place with the repoptdating of the glaciated areas 

 after the retreat of the ice, using as data the present happenings on river-bed at 

 the terminal faces of glaciei-s, on </^6r(V. and so on. 



The various soils are discussed, espei-ially the wind-blown rock-flour, the 

 "loess"' of the amhoi-s. The climate of the district is classified as steppe and 

 foi-est climate, and the limits of these are defined. 



Wind is cited as an ecological factor of paramoimt importance. 



The mechanical and physiological effects of snow are briefly discussed, also its 

 relation to the installation of steppe or fellfield psychrophytes. Short periods of 

 drought are c-onsidei"ed to stivngly favour xeromorphy. 



The body of the paper deals with the plant -associiUions. and the growth-forms 

 of their members. T^e vegetation is treated of from the dj-naraical standpoint, 

 and the associations fall into two categories — namely, the steppe series and rock- 

 fellfield series, or. in the foi-est climate, the i-ock-forest series. It is further shown 

 how the same climax asso<"iation may arise from different beginnings. 



The paper concludes with a list of species noted in the district, anranged 

 according to the system of Engler, and a short bibliography. 



