464 TRANSACTIONS OF SOCIETIES. 



RovAL Society of South Africa. — Wednesday, May 20th : L. Perin- 

 guey, D.Sc, F.E.S., F.Z.S., President, in the chair.^" Pliosphorcscctit bac- 

 teria from the sea round Robben Island": Dr. H. Bayon. Pure cultures 

 were exhibited, showing various degrees of kuninosity. The identification 

 of the bacteria not being completed, exhibitor was not ready to state that 

 these vibrios differed sufficiently from the micro-organisms observed in 

 other parts of the world, to allow the classification of a separate variety. 

 Attention was brought to the various conditions under whicii these bac- 

 teria lost and acquired again their luminous properties, both in relation to 

 special media and aerobic conditions. — " A trypanosome and hccmogrc- 

 garinc from the mole shark (scilliorhinus edwardsii.)'' : Dr. H. Bayon 

 Microscopical specimens of these two new blood parasites were exhibited, 

 and their life-cycle and transmission through an intermediate host (prob- 

 ably of the nature of a leech) were explained.- — "Properties of Pfaffians 

 and their analogues in determinants " : Dr. T. Muir. — " The secular varia- 

 tion of the magnetic elements in South Africa during the period 1900-1913. 

 Prof. J. C. Beattie. The annual changes in the magnetic declination 

 vary from an average decrease of 1.5' of westerly declination at 

 Mauritius during 1900- 1909 — a change which has turned into an increase 

 of 1.4' per year between 1907- 1909 — to a decrease of 14' per year in the 

 neighl)ourhood of Durban ; from the latter place the decrease becomes 

 less a.s we go in a north-westerly direction and attains a value of 5' at 

 Laonda ; the decrease as we go west or south-west is also quite; 

 definite, tliough not so great, and at Capetown has the value of 8'. It 

 appears also that the absolute value of the decrease is increasing all over 

 South i\frica at the present time. A compa'rison of the results given 

 with those of the American and British Admiralty declination charts for 

 approximately the same epoch shows no continuity between the land 

 values of the secular change and those over the sea, the high values over 

 the land find no place over the sea except in the case of the result 

 obtained from the Gauss and Carnegie observations. The greatest annual 

 change of dip is found in the south-western part of the continent in the 

 neighbourhood of Capetown ; it amounts to an increase of southerly dip 

 of 8' per year. The line of no change passes through Madagascar, east 

 of that there is a decrease of southerly dip. The annual change in the 

 horizontal intensity shows a decrease in absolute magnitude towards the 

 north ; over the greater part of the Union it has a value of from 80 ry to 

 100 y yearly, and is a decrease. 



tiTLE PAGE AND INDEX. 



The Index to V-'oluine X is in course of ])reparation, and will 

 l)C forwarded to Members and Subscribers in due course, with 

 the 'I'itle Page, Contents and Report. At the same time particu- 

 lars with regard to arrangements for binding the volume will be 

 announced. 



