The price of this Journal to the general public is as marked on the front page. 

 Every member of tlie Association is supplied with one copy free, and may obtain 

 extra copies at half-price. Applications for copies should be addressed to the 

 Assistant General Secretary, P.O. Box 6894, Johannesburg. 



CORRESPONDENCE. — All communications other than those relating to the 

 Journal Should be addressed to the Assistant Secretary, P.O. Box 6894, Johannes- 

 burg. (Telegraphic address: "Science, Johannesburg.") 



Communications for the Editor should be addressed to P.O. Box 1176, 

 Johannesburg. 



PAPERS for publication should be typewritten. 



ILLUSTRATIONS (other than photographs) accompanying papers intended 

 for publication in the Journal must be supplied by the authors, carefully drawn 

 about twice the size of the finished block, on smooth white Bristol board, in Indian 

 ink, so as to admit of the blocks being prepared directly from the drawings. Any 

 lettering on these drawings should be of such a size that it will be clearly legible 

 when reduced. 



REPRINTS* — Authors desiring to have reprints of their papers, read at the 

 Annual Meeting of the Association, are requested to notify the Editor as soon 

 as possible as to the number required, or, at latest, when returning their proofs. 



LOOSE COVER CASES. — Cases uniform with the covers of previous volumes 

 may be obtained for binding on application to the Assistant General Secretary, 

 at a cost of 5s. per case post free. 



SUBSCRIPTIONS.— Subscriptions of £1 10s. for the year ending 30th June, 

 t923, are now due. Members are requested to be so kind as to remit the amount 

 as soon as possible to the Assistant General Secretary, P.O. Box 6894, Johannes- 

 burg. Unless members pay the amount due at an early date, great inconvenience 

 and unnecessary expense may be caused, as it is very difficult to determine what 

 number of copies of the Journal will be required. The Council therefore appeals 

 to evei'y member for support and co-operation, and asks that outstanding subscrip- 

 tions be paid without delay. The Journal will be sent only to those whose arrear 

 subscriptions are paid. 



Cheques, etc., should be crossed and made payable to the Association, not to 

 the Secretaries or Treasurer individually. Sixpence should be added to country 

 cheques for exchange. 



HEADQUARTERS.— The office address of the Association now is " P.O. Box 



Gb94, Johannesburg"; the telegraphic address is "Science, Johannesburg"; and 

 the telephone number " 1404, Johannesburg." 



Johannesburg, 31st December, 1922. 



