Jan., 1889. 
6 spencer's “first principles.” 
As regards the migration of this plant, it may be 
noticed that all the localities where it has been found in 
Germany, Sweden, and Norway, are on the West coast, 
exposed to the influence of the Gulf Stream; and the flower 
is a composite with winged seeds, which admit of being 
carried long distances by an ocean current. 
( To be continued.) 
THE FOUNDATIONS OF OUR BELIEF IN THE 
INDESTRUCTIBILITY OF MATTER AND THE 
CONSERVATION OF ENERGY.* 
A CRITICISM OF SPENCER’S “FIRST PRINCIPLES,” 
Paut II., Chapters IV., V., and VI. 
BY J. H. POYNTING, D.SC., F.R.S. 
I confess that when I accepted the invitation to give a 
paper on the chapters in Spencer's “First Principles” dealing 
with the Constancy of Matter, Motion, and Force, I had no 
idea of the difficulty of the task which I was undertaking. 
I remembered that when, many years ago, I read the chapters 
I disagreed with their general drift, and I thought it would be 
tolerably easy to disagree still. And so I have found it. But 
it is one thing to disagree with an author, and quite another 
thing to give clear reasons for your disagreement, especially 
when the subject is so difficult and your author is so great a 
master of argument as Spencer. And there is to me another 
difficulty in that I have never studied Spencer’s system as a 
whole. The chapters I am to deal with form but a part of 
that whole ; one staircase, as it were, in a grand edifice, 
which vou have watched building stone bv stone. I am 
venturing to criticise this particular staircase when I have not 
studied the plans of the building, and know not whence it 
springs or whither it leads. I am a mere carpenter venturing 
to criticise the work of a great architect. I don’t know that 
I am even a carpenter. I have been, for many years, especially 
engaged in teaching people how to climb this particular kind 
of staircase, and perhaps you may think that that is hardly a 
* Read before the Sociological Section of the Birmingham Natural 
History and Microscopical Society, November 22, 1888. 
