THE NEW ZEALAND BOARD OF SCIENCE AND ART. 
THE 
NEW ZEALAND 
JOURNAL OF SCIENCE 
AND 
TECHNOLOGY. 
VOLUME IV. 
Edited by 
Dr. J. ALLAN THOMSON; 
Assisted by 
Professor C. A. COTTON, Mr. S. H. JENKINSON, and 
Professor E. MARSDEN, Wellington. 
Professor A. P. W. THOMAS, Auckland, 
Professors C. CHILTON and R. J. SCOTT, Christchurch, 
and 
Professor W. B. BENHAM, Dunedin. 
Issued under the authority of the Hon. W. DOWNIE STEWART, 
Minister of Internal Affairs. 
WELLINGTON, N.Z. 
By Authority : Marcus F. Marks, Government Printer. 
1922. 
