474 
be to repeat almost the same story about 
other things. If our present knowledge of 
electricity is essentially the child of the 
nineteenth century, so also is our present 
knowledge of many other branches of 
physics. And those most ancient forms of 
exact knowledge, the knowledge of numbers 
and of the heavens, whose beginning is lost 
in the remote past, have, with all other 
kinds of natural knowledge, moved onward 
during the whole of the hundred years with 
a speed which is ever increasing. I have 
said, I trust, enough to justify the state- 
ment that in respect to natural knowledge 
a great gulf lies between 1799 and 1899. 
That gulf, moreover, is a two-fold one: not 
only has natural knowledge been increased, 
but men have run to and fro spreading it as 
they go. Not only have the few driven 
far back round the full circle of natural 
knowledge the dark clouds of the unknown 
which wrap us all about, but also the many 
walk in the zone of light thus increasingly 
gained. Ifit be true that the few to-day 
are, in respect to natural knowledge, far re- 
moved from the few of those days, it is also 
true that nearly all which the few alone 
knew then, and much which they did not 
know, has now become the common 
knowledge of the many. 
What, however, I may venture to insist 
upon here is that the difference in respect 
to natural knowledge, whatever be the case 
with other differences between then and 
now, is undoubtedly a difference which 
means progress. The span between the 
science of that time and the science of 
to-day is beyond all question a great stride 
onwards. 
We may say this, but we must say it with- 
out boasting. For the very story of the 
past which tells of the triumphs of science 
bids the man of science put away from him 
all thoughts of vainglory—and that by 
many tokens. 
Whoever, working at any scientific prob- 
SCIENCE. 
[N.S. Vou. X. No. 249. 
lem, has occasion to study the inquiries into 
the same problem made by some fellow- 
worker in the years long gone by, comes 
away from that study humbled by one or 
other of two different thoughts. On the 
one hand he may find, when he has trans- 
lated the language of the past into the 
phraseology of to-day, how near was his 
forerunner of old to the conception which 
he thought, with pride, was all his own, not 
only so true but so new. On the other 
hand, if the ideas of the investigator of old, 
viewed in the light of modern knowledge, 
are found to be so wide of the mark as to 
seem absurd, the smile which begins to play 
upon the lips of the modern is checked by 
the thought, Will the ideas which I am now 
putting forth, and which I think explain so 
clearly, so fully, the problem in hand, seem 
to some worker in the far future as wrong 
and as fantastic as do these of my fore- 
runner to me? In either case his personal 
pride is checked. Further, there is written 
clearly on each page of the history of science, 
in characters which cannot be overlooked, 
the lesson that no scientific truth is born 
anew, coming by itself and of itself. Hach 
new truth is always the offspring of some- 
thing which has gone before, becoming in 
turn the parent of something coming after. 
In this aspect the man of science is unlike, 
or seems to be unlike, the poet and the 
artist. The poet is born, not made; he 
rises up, no man knowing his beginnings; 
when he goes away, though men after him 
may sing his songs for centuries, he himself 
goes away wholly, having taken with him 
his mantle, for this he can give to none 
other. The man of science is not thus 
creative ; he is created. His work, how- 
ever great it be, is not wholly his own; it 
is in part the outcome of the work of men 
who have gone before. Again and again a 
conception which has made a name great 
has come not so much by the man’s own 
effort as out of the fullness of time. Again 
