135 
Mar. 31, 1910. The Queensl^vnd Naturalist. 
able to test the question as to whether species have arisen 
from the accumulation of minute variations or not. 
37. — The crucial point is not whether evolution is 
true. That seems for ever settled in the affirmative. It 
is the question of the how ; whether by slow or by rapid 
steps, whether ])er saltum or otherwise, and i believe we 
can now answer that momentous ([uery. 
38. In the face of all tlie accumulated knowledge 
of to-day, no theory can stand which is based u])on negative 
evidence. Half a century ago anyone might formulate 
any theory leaning on the non-existent reed of the imper- 
fection of the geological record. That intangible possibility 
is now replaced by a very tangible support which is not 
negative but positive evidence ; l)ut it has the difficult task 
of attempting to oust accepted theories — ghosts — in which 
many believe, because they were so taught, and alas ! 
which some find to be lucrative orthodoxy. We have 
been and are filling in the ijeological gaps rapidly, and the 
palceontological gaps ought to be closing pari passu. 
III. — Mathematic and Geological Time. 
^ 9 . — All hypotheses, and most theories, must be in 
advance of facts. The test of their truth (as distinct from 
their value as working tools) is that not only do they 
explain known phenomena, but they point the way to fresh 
discovery. 
40. — Now Mathematic is as ])rogressive as any other 
])hase of science, but neithei' more nor less exact. The 
mathematician, however, is like a rain-drop, he must 
gather about a nucleus. But he has an unholy aptitude 
for nuclei, and sometimes he ])iles a brilliant spheroid 
around an unworthy centricle. But not often. I would 
that more geologists were mathematicians. To me, if I 
may be personal, modern mathematical analysis is as music 
— as symphonies I love and appreciate, but could not 
compose. I read their wondrous results with delight, and 
accept ail their statements as true deductions from their 
premises. 
41. — The mathematicians threw the first bomb 
among the sleepy geologists and palyenotologists and 
evolutionists who thought their unlimited draft on the bank 
of time was backed by eternity. In the year 1880, Sh 
William Thomson (afterwards Lord Kelvin) quietly drove 
in the geological ai d biological earthworks by the 
announcement that th ir supply of time (like Brisbane’s 
water in the hot seaso; ) was to be cut off. And he did it 
vigorously. He said (;.nd proved) you can’t go on draw- 
ing upon the sun, beca ise his cash is running out, and you 
mustn’t delude folk with the idea that he was always your 
banker, because a ie\/ million years ago you and your 
