432 NOTICES OF THE MEETINGS. [April 28, 
From all these considerations, the numbers of species in a group 
or genus at any given epoch is to be excluded, not being an ele- 
ment in the discussion of the question, though apt to be introduced 
through mistake of the nature of the generalization attempted to be 
attained. 
There may appear to be a contradiction involved in the expression 
manifestation of polarity in time, for since time implies sequence or 
progression in one direction only, how can we connect with time an 
arrangement that involves the notion of progression in opposite 
directions, proceeding from a median zero? 
But time is an attribute with which man’s mind invests creation; 
a mode of regarding Divine ideas, necessary for the conception of 
time by our limited faculties and forming in itself no part or 
essence of the Divine scheme of organized nature. We speak of 
Polarity in Time, for want of a better phrase: but this polarity, or 
arrangement in opposite directions with a development of intensity 
towards the extremes of each, is itself, if 1 am right in my specula- 
tions, an attribute or regulating law of the divinely originating 
scheme of creation, therefore strictly speaking independent of the 
notion of time, though perceptible by our minds only in connection 
with it. 
By a diagram such as the above we may fairly express this view, 
the shaded portions of the circles included within the great circle 
of the system of nature representing the maxima of development 
of generic ideas, and the dotted area, z, the region of their minimum 
productions. 
In venturing on a speculation of this kind I am aware that it is 
subject to much misrepresentation and liable to be misunderstood ; 
the more so since the suggestion must precede the demonstration. 
At present it can scarcely be received as more than a suggestion ; 
one put forth as worthy of consideration. But in issuing it I do so 
keeping in view a vast number of individual facts and base it upon 
the results of investigations of no small extent. To lay these before 
the scientific world in detailed and tabulated shape will be the work 
of more leisure than can at present be given to the task. In the 
hope of acquiring fresh data for this investigation I, rashly as 
some may think, make public this hypothesis. That it is the only 
