SCIENCE AND INDUSTRY. 
The Imperial Aspects of Chemical 
| Science.” 
By PROF. SIR WM. J. POPE, F.R.S. 
When the student of the future is able to survey dispassionately the 
history of the nineteenth and the earlier part of the twentieth century 
he will, without doubt, insist strongly upon the very distinct way in 
which these two periods are differentiated from every preceding era. 
The vast expansion of the experimental sciences which took place 
around the opening of last century led to an entire change in the 
outlook of mankind upon the external world. From prehistoric times 
until the introduction of the locomotive, the steam-ship, and the electric 
telegraph, means of communication had remained practically stationary. 
The transport arrangements made by Cxsar for landing his legions 
in Britain were.to all intents and purposes identical with those made, 
more than eighteen centuries later, when Wellington took his armies 
to the Continent to fight Napoleon; such minor differences as existed 
arose from the introduction. of the firearm as a scientific weapon. 
The obstacle placed by geographical distance in the way of human 
inter-communication had preserved its magnitude unchanged from time 
immemorial; it has diminished progressively throughout the last cen- 
tury, and the past twenty years have seen it reduced to comparative 
unimportance by the advent of the aeroplane. It is safe to predict that 
before the middle of the twentieth century men and goods will be 
transportable between any two points on the earth’s surface in less than 
twenty-four hours. 
Some, at least, of the methods involved in this remarkable develop- 
ment of human powers of locomotion are easily understood by any one 
not possessed of the knowledge of a specialist. Man has acquired, 
by the invention of special appliances, the power of concentrating energy 
into small weight and compass, and using it for purposes of locomotion; 
the details may be obscure, but the general result—that if a man can 
control and handle mechanical power far greater than that exercised 
by his own muscles, he can achieve feats of movement and action quite 
beyond attainment by the naked savage—is quite incomprehensible. So 
soon, however, as we pass from the consideration of the purely mechanical 
to certain of the other great forces of nature, difficulties in exposition 
and comprehension seem to arise. It appears easy to understand the 
working of powerful mechanical appliances because their effects are 
but multiples of those produced by our own limbs; it seems difficult to 
the non-technical person to grasp why that intimate mixture of three 
such inert materials as sulphur, charcoal, and nitre, which we call gun- 
powder, should be capable of exploding with a loud detonation and with 
violently disruptive effects. Nature has given us some intuitive power 
of understanding purely mechanical effects, those being needed in our 
a a aa ee 
* A Lecture delivered before the Royal Dublin Society on 4th February, 1920. 
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