THE NEW CHEMISTRY, A DEVELOPMENT OF THE OLD. 121 
I have thus sought to substantiate the claim of the new 
chemistry to he a development of the old. I believe that if 
this claim is granted, the conclusion to be drawn must be, not 
that the old is better, but that to return to that which is 
admittedly an early stage of development would be to misread 
all the teachings even of the old chemistry itself. 
One general lesson may surely be deduced from what has been 
said, and that is, the continuity of science. Science proceeds by 
gradual developments, each dependent on that which went 
before. She may frequently be obliged to review her past 
progress, and even, in the light of freshly acquired knowledge, 
to alter what once appeared to be well-established general- 
izations. But if any generalization of science be founded on 
experimentally authenticated facts, it always survives, although 
not necessarily in its commonly accepted form. The Phlogistic 
theory was absorbed in, not entirely contradicted by, the Caloric 
theory of Lavoisier, which in its turn was merged in the fuller 
and more definite modern doctrine of Energy. The dualism of 
the Swedish school appeared to be absolutely overthrown by 
the followers of Dumas, but the theory has survived, and, 
modified to suit the conditions of its environment, forms one of 
the groundworks of the chemistry of to-day. 
In examining the progress of Science, we see that she is not 
afraid to retrace her steps, and that she is able to retain and 
develop all that is probably true, whilst rejecting all that is 
proved to be false ; and when we learn that she does this, can 
we hesitate to find in her history the ‘ promise and potency ’ of 
a mighty future ? 
Caitjs College, Cambridge; 
February , 1880 , 
