poe wet TE 
NOTICE. 
THe Roya Sociery of New South Wales originated in 1821 as 
the “Philosophical Society of Australasia”; after an interval of 
inactivity, it was resuscitated in 1850, under the name of the 
‘¢ Australian Philosophical Society,” by which title it was known 
until 1856, when the name was changed to the “ Philosophical 
Society of New South Wales”; in 1866, by the sanction of Her 
Most Gracious Majesty the Queen, it assumed its present title, 
and was incorporated by Act of the Parliament of New South 
Wales in 1881. 
NOTICE TO AUTHORS. 
The Honorary Secretaries request that authors of papers (to be 
read before the Royal Society of New South Wales) requiring 
illustrations by photo-lithography, will, before preparing such 
drawings, make application to the Assistant Secretary for patterns 
of the standard sizes of diagrams We. to suit the Society’s Journal. 
ERRATA. 
Page 200, line 2, after ‘expression ” insert ‘ Neglecting H in 
comparison with B”, 
Page 205, Corollary (1i.), line-5, . 
= —}*(BH—}H?) 
3 
UE = LeU)? 
or faa | 
should read 
B2 — H? 1 
t ss (IR BE aa en Bre 
Sar rea 2) 
BB? 2-8 A 
or 
Sir 
Page 227, line 18 from top, for “ points,” read ‘“ joints.” 
