g8 The Australasian Scientific Magazine. [Oct. i, [885. 
entered upon. But those who have not had their love of country stifled 
by the conventionalities and systematised teaching of modern life will 
rejoice that one holding such a recognised position in the scientific world 
as Sir John Lubbock thinks the study of the forms of leaves worthy of 
attention. It is an open-air study. In his discourse at the Royal Institu- 
tion on “ The Forms of Leaves,” he pointed out how much there is to 
observe in the adaptation of their size and shape and relative position, and 
in the proportion of the size of the stem to the surface of the leaf. “The 
reign of law” is to be traced here, though so little attention has been paid 
to the subject. The distance leaves are apart, the shape that groups of 
them assume, their thickness and symmetry, or unsymmetry, all are interde- 
pendent. The details he brought forward he spoke of as only an outline 
sketch of observations to be made, and these were put forward in a way 
that demands neither the credence of the evolutionist nor of the believer 
in design. The facts are simple observations in themselves. The obser- 
vations are on the lines of the old-fashioned field botanist, and lead men 
out to the meadow and the woodland. 
ON PROBABILITIES. 
BY 
ROBERT THOMSON, F.I.A. 
No. I. 
The “doctrine of chances” has been a fascination to mankind in all ages. 
Mighty events have been ruled by the fatal hazard of a die. 
The schoolboys play at “pitch and toss.” Supposing each boy to be equally 
skilful, in the long run each would remain as he began, neither richer nor 
poorer. But if the game went on for only a few throws, there is a strong likeli- 
hood that one of the boys would be the possessor of the coppers of the other. 
Supposing one boy by study has arrived at a knowledge which the other 
does not possess, that he can regulate the momentum of the half-penny he 
“ skies,” so that he can judge with some degree of probability whether his 
throw will turn up head or tail, he has the advantage of his opponent. He 
calculates his probabilities, crudely enough no doubt ; but to a certain 
extent he has the advantage of his competitor. Even with perfectly fair 
