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certainty possessed by experimental inquiry is here shut 

 out, the imagination is not left entirely without guidance. 

 From the examination of the solar system, Kant and 

 Laplace came to the conclusion that its various bodies 

 once formed parts of the same undislocated mass ; that 

 matter in a nebulous form preceded matter in a dense 

 form j that as the ages rolled away heat was wasted, 

 condensation followed, planets were detached, and that 

 finally the chief portion of the fiery cloud reached, by 

 self-compression, the magnitude and density of our sun. 

 The earth itself offers evidence of a fiery origin ; and 

 in our day the hypothesis of Kant and Laplace receives 

 the independent countenance of spectrum analysis, 

 which proves the same substances to be common to the 

 earth and sun. Accepting some such view of the con- 

 struction of our system as probable, a desire immediately 

 arises to connect the present life of our planet with the 

 past. We wish to know something of our remotest an- 

 cestry. 



On its first detachment from the central mass, life, as 

 we understand it, could hardly have been present on the 

 earth. How then did it come there ? The thing to be 

 encouraged here is a reverent freedom a freedom pre- 

 ceded by the hard discipline which checks licentiousness 

 in speculation while the thing to be repressed, both in 

 science and out of it, is dogmatism. And here I am in 

 the hands of the meeting willing to end, but ready to 

 go on. I have no right to intrude upon you, unasked, 

 the unformed notions which are floating like clouds or 

 gathering to more solid consistency in the modern spec- 

 ulative scientific mind. But if you wish me to speak 

 plainly, honestly, and undisputatiously, I am willing to 

 do so. On the present occasion 



You are ordained to call, and I to come. 



