Contents. 
PAGK 
Heating and Cooling Apparatus for Eontgen Crystallo- 
GRAPHic Work. By J. Steph. van der Lingen. (Eight Text- 
figures) ........... 647 
The Arrangement of Successive Convergents in Order of 
Accuracy. Bv Alexander Brown ...... 653 
The Use of a Standard Parabola for Drawing Diagrams of 
Bending Moment and of Shear in a Beam Uniformly 
Loaded. Bj Alexander Brown. (Four Text-figures) . . 659 
Further Magnetic Observations in South Africa during 
THE Years 1913-1915. By J. C. Beattie, D.Sc. . . .669 
True Isogonics and Isoclinals for South Africa for the 
Epoch July 1, 1913. Bv J. C. Beattie, D.Sc. (Two folding 
Maps) 671 
The Heating Coefficients of Rheostats and the Calculation 
OF Resistances for Currents op Short and Moderate 
Durations. By H. Bohle. (Seven Text-figures) . . . 685 
Note on the So-called Yahlen Relations between the Minors 
OF A Matrix. By Sir Thomas Muir 695 
Descriptions of some New Aloes from the Transvaal. — Part 
II. By I. B. Pole Evans. (With Plates L— LYI) . . 703 
South African Perisporiales. I. Perisporiaceae. By Ethel M. 
Doidge, D.Sc, F.L.S. (With Plates LYII— LXYI) . . 713 
