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

 page. Every member of the 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, 



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



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

 Johannesburg. 



MANUSCRIPTS 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 oli 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 t-o notify the Editor as 

 to the number required 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 4s. per case post free. 



BINDING VOLUME XVI.— The publication of vol. xvi of the Journal, 

 comprising the papers read at the Kingwilliamstown (1919) meeting, is now 

 comp.'eted. Members desiring to have their separate numbers of this volume 

 bound should forward them to the Assistant General Secretary, and inform 

 him of their wishes, when the orders will be given to the binders. The cost of 

 the cover and binding will be 12s. 6d. post free. 



SUBSCRIPTIONS. — Subscriptions of £1 10s. for the year ending 

 30th June, 1922, 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, Johannesburg. Unless members pay the amount due at an 

 early date, great inconvenience and unnecessary expense may be caused, as it 

 is very diflficult to determine what number of copies of the Journal will be 

 required. The Council therefore api^eals to every member for support and 

 co-operation, and asks that outstanding subscriptions be paid without delay. 

 The Journal will be sent only to those whose arrear subscriptions are paid. 



Cheques, etc., should be crossed and made j^ayaljle to the Association, 

 not to th© Secretaries or Treasurer individually. Sixpence should be added to 

 country cheques for exchange. 



HEADQUARTERS. — Attention is called to the change of Headquarters 

 decided on at the KingwilliaJnstown (1919) session. The oifice addi-ess of 

 the Association now is "P.O. Box 6894, Johannesburg"; the telegraphic 

 address is " Science, Johannesburg," and the telephone number " 1404, 

 Johannesburg . ' ' 



Johannesburg, 30th April, 1921. 



