347 
mulated at the present day, the advance of science since their 
time has been immense, but if we fairly compare their phi- 
losophy of the earth with that reasoning as to the causes of 
terrestrial changes which prevails in even the highest quarters 
now, I am not sure that progress can be reported as of so 
great a measure. Fire and water unitedly filled up their 
thoughts of causation, so far as the surface of the earth was 
concerned, and these two well-known agencies seem to occupy 
the same space in the thoughts of modern philosophers. The 
forces that produce fire, and give water its power to dissolve, 
and which must be considered before many of the greatest 
facts in the eartlds history can be explained, are nearly, if 
not quite, as much unknown to the moderns as they were to 
the ancients. Perhaps here the comparatively superficial 
thinker will remember Newton and gravitation.' 5 '’ The 
more careful thinker will remember Faraday, who says that 
force is “ matter.-” Gravitation,” he says, ce is a property 
of matter depending on a certain force, and it is this force 
which constitutes matter.”* He will ask whether either Newton 
or Faraday really knew what gravitation is. He will find it 
very difficult to think that they did so. He will deeply ponder 
the manner in which the most favoured of the moderns rea- 
son on the effects of forces ; exaggerating the least, and 
forgetting the greatest. And he will be constrained to give 
the ancients credit for a very great amount of geological 
science — that is, when that which they knew is weighed 
against that which is known at the present hour. There is 
a dangerous vanity which feeds on imaginary progress in 
knowledge, and needs often to be made aware of the fanciful 
character of that on which it thrives. I am persuaded that 
few things are more salutary in the way of restraining this 
vanity than an honest and patient comparison of what even 
the heathen thinker knew with the actual science mastered by 
the most civilized and enlightened among ourselves. 
When we leave the period of observation and reasoning 
represented by such men as Herodotus and Pliny, and endea- 
vour to find some tufts of truth on which to place our feet as 
we pass through the morass of stagnant and phosphorescent 
thought which followed that time, we feel greatly at a loss. 
For nearly fifteen hundred years rational inquiry stood as still 
as if progress had ceased to be a feature in humanity. It is, 
* Faraday’s Researches , vol. ii. p. 293. In this remarkable utterance 
gravitation is not a force but a property of a force. It is a property of 
matter, but then that is constituted by, or, in plainer words, is a certain 
force. So gravitation is a property of a force depending on a certain force, 
which force is just force ! 
