66 
NATOKRE. 
[Mov. 16, 1882 
many blanks in the records have been filled up, and our know- 
ledze will doubtless be yet greatly increased, it must nevertheless 
be admitted that this knowledge must always bear but a very 
small proportion to our ignorance. In this, however, there is 
nothing to discourage us, as we may be quite sure that the work 
remaining to be done will far exceed all the energies of many 
generations to accomplish. 
It is sometimes objected to Geology that its results are not 
always s> exact as those which are obtained by an experimental 
science like chemistry. We are reproached with the fact that 
our theoretical conceptions undergo frequent modification, and 
are even often abandoned, to be succeeded by others which, 
after flourishing for a time, are in like manner overturned and 
thrown aside. But the same reproach, if it be one, might be 
brought against other sciences. Each advancing science has 
its problems and speculations. And we cannot often feel 
assured that the solution now given of those problems will in all 
cases stand the test of time. Our theoretical conceptions of the 
ultimate constitution of matter, for example, have within com- 
paratively few years undergone considerable change, and yet no 
one values chemistry the less. Let our theories be what they 
may, they do not and cannot overturn the results obtained by 
verified observation and often repeated and varied experiment. It 
remains for ever true that water is composed of oxygen and hy- 
drogen, let our views of the atomic theory change as they may. 
And so it is not less certain that strata of conglomerate and sand- 
stone containing marine or fresh-water fossils are of aqueous 
origin, however much our theoretical conce ‘tions may vary as to 
the uniformity in degree between the past and present opera- 
tions of Nature. It is true we did not see the conglomerate 
and sindstone in process of formation, but we know by obser- 
vation that these rocks exactly resemble deposits of gravel and 
sand which are now being accnmulated in water. Nature in 
this case makes the experiment for us, whereas the chemist has 
to do this for himself. The latter, havinz well ascertained by 
varied experiments the composition of certain samples of water, 
henceforth c ncludes that all water is made up of the same two 
gases in definite proportions. But this conclusion of his is just 
as much an assumption as the inference of the geologist that 
strata containing marine or freshwater fossils are aqueous accu- 
mulations. It i; when we come to the larger generalisations of 
our science that we are more likely to go astray. The problems 
we have to solve demand not only an accurate knowledge of 
widely scattere1 phenomena, but a ready command of logical 
analysis. The facts may be sufficiently abundant, but if we 
reason badly we of course miss their meaning. Or, on the other 
hand, the evidence may be more or less imperfect. There are 
blanks which we fill up with conjecture—which can do no harm 
s» long as we do not treat our conjectures asif they were facts. 
But when the gaps in the evidence are numerous, each theoriser 
will fill them up after his own fashion, and very various results 
will thus be obtained. Even in cises of this kind, however, a 
rigorous application of logical analysis will enable us to detect 
the fallacies which may underlie all the competing theories ; and 
we are thus prepared t» frame a new exolanation for ourselves, 
and to set about searching for additiona] facts to prove or dis- 
prove our notions. In all such investigations it is obviou-ly the 
duty of a careful observer and theoriser to see well to his pre- 
mises—to be absolutely sure as to his facts, and to distinguish 
clearly between what is substantial knowledge, and what is 
mere conjecture. He will thus be in a position to judge whether 
his conciusions are based on a solid foundation or not. Ina 
science of observation like geology, theory is necessarily often 
in advance of the facts. Some, indeed, have insisted that all 
conjectural explanations are quite a mistake; that it would be 
better to avoid theorising altogether, and to wait patiently until 
the chain of evidence had completed itself. I am afraid that, 
were it possible to follow this advice, we might often have to 
wait a very long time. After all, a heap of bricks is only a 
potential house: it will not grow up into walls without the aid of 
architect and builder. Discoveries in science have no doubt 
been made occasionally by isolated and haphazard observations ; 
but that is exceptional, and we should not be where we are now 
had the examination of Nature been always conducted after such 
a fashion. If additional evidence be required, we must first 
have some notion where to look for it. In other words, it is 
essential to progress that we should have preconceived opinions 
or theories, which enable us to arrange the facts we already pos- 
sess, and to point out the directions in which further evidence 
may be looked for. We cannot be too careful, however, that 
our preconceived notions do not lead us to colour the evidence 
or to blind us to facts that tell against our views. Every theory 
should be considered provisional until its truth has been fully 
demonstrated by an overwhelming array of testimony in its 
favour. Until this consummation is arrived at we must be con- 
stantly testing its truth, and be ready to abandon it at once 
whenever the evidence shows it to be erroneous, The failure of 
one theory after another need not disconcert or discourage us ; 
for each failure, by reducing the number of possible explana- 
tions, must necessarily bring us nearer to our goal—the truth. I 
cannot but deem it a strong point in favour of geology asa branch 
of education that it not only cultivates the faculty of clear and 
continuous observation, but abounds in unsolved problems 
which are ever suggesting new ideas and thus stimulating that 
imagination which is one of the noblest gifts of our race. It is 
no reproach that the progress of our science is marked by the 
modification and abandonment of numerous hypotheses and 
theories. On the contrary, these afford a measure of the rate 
at which geol gy advandes—just as this last yields the strongest 
testimony to the good results that accrue from having some 
provisional view by which to direct the course of our observa- 
tions. 
It is unavoidable that in the onward march of a science the 
facts become at last so numerous as to task all the energies of its 
votaries to keep abreast of their time. When a beginner first 
surveys the wide field embraced by geological inquiry, he may 
not unnaturally experience a feeling akin to despair. How is it 
possible, he may think, that I can master all these manifold 
details—how can I test the truth of all those numerous inferences 
and conclusions—ard yet have sufficient leisure and energy left 
to undertake orizinal observation? Well, no one can hope to 
advance the science in all its departments. When we reflect 
that in order to obtain a complete comprehension and mastery 
of the existing condition of things we should require to be 
adepts in physics, mechanics, chemistry, and every branch of 
natural science, it is obvious that such a perfect knowledge is 
beyond attainment. It is needless, therefore, that we should 
strive to become ‘‘admirable Crichtons” in this nineteenth 
century, and no beginner need be discouraged by jhe greatness 
of the science which he desires to cultivate. It is only by divi- 
sion of labour that so much has been accomplished ; and the 
results are now so systemutised that it is quite possible for any 
intelligent inquirer to gain a thorough comprehension of the 
principles of the science. But this it is absolutely necessary 
to acquire, and the student, therefore, should at first devote all 
his energies to learn as much as he can of those principles and 
their application. When he has progressed so far, he is then 
ready to set out as an explorer in the well-assured hope that if 
he be true to the logical methods which have hitherto succeeded 
so well, he will not fail to reap his reward in the discovery of 
new truths, But to secure success we must be content to be 
specialists. In other words, we must concentrate our energies 
ulon some particular lines of inquiry, and do our utmost to 
work these out in all their details. At the same time we should 
make a great mistake if we aid not always keep in mind the 
broader bearings of our science, and endeavour to maintain as 
wide a knowledge a3 we can of all its branches. Each of these, 
we may be sure, has something to tell which will aid us in our 
own special inquiries. We cannot, therefore, afford to neglect 
the side-lights which are thrown upon our path from the lamps 
of others who are working in adjacent fields. One cannot help 
thinking that many specialists would have given us more and 
better work if they had not allowed themselves to be cramped 
and narrowed by continuing too long in one rut or groove. They 
dig so deep that they get into a hole out of which it is some- 
times difficult to climb, and thus not infrequently the work 
being done by fellow-labourers, escapes them, and they miss the 
suggestions which a knowledge (of that work might otherwise 
have yielded them. 
Ihave said nothing as to the practical applications of our 
science—that branch of our subject which is termed economic 
geology—not because I consider it the less important, but 
because its value is generally recognised and need not now be 
insisted upon. Many, I do not doubt, enter upon their 
geological studies with a distinct view of obtaining from the 
science such help as it can afford them in the practical pursuits 
of life. To such inquirers it will be my pleasure not less 
than my duty to give every assistance that is in my power. 
But I would point out to them that there is no short cut to the 
attainment of the knowledge they are in quest of. The study 
