Kahlenberg—Factors in Scientific Research . 1295 
Theories, hypotheses and notions are very helpful when 
rightly used. They have a very important function in sug¬ 
gesting new avenues of attack by experiment and observation. 
But it must also he pointed out that theories and hypotheses 
suggest by implication that certain things are impossible and 
that it would be a foolish waste of time to look for such things, 
which are often quite possible. Thus, theories are frequently 
a hindrance and a stumbling block. And yet they often take 
such complete possession of men that they amount to convic¬ 
tions and can not be shaken by any means whatever. They 
then become what we might well term scientific creeds. So it 
was believed by the great Stahl that when substances burn a 
subtle principle, phlogiston, flies out of them. He expounded 
this enthusiastically in detail, and gained a great many ardent 
disciples who tenaciously stuck to his view, and defended it. 
Even the discoverers of oxygen themselves, the great Scheele and 
Priestley, were followers of Stahl and defended the phlogistic- 
view of combustion as long as they lived, holding that Lavoi¬ 
sier’s idea that combustion in the air consists of union with 
oxygen was untenable in spite of the quantitative experiments, 
on increase of weight during combustion which the latter de¬ 
scribed. Thus we see that scientists and theologians are not 
made of different clay when it comes to adhering tenaciously 
to preconceived notions, expounding these and making disci¬ 
ples. Think of the idea of evolution of Darwin and how 
Huxley fought for it through thick and thin, and are we after- 
all so cocksure of the matter at present ? It took some time to 
establish the notion that a chemical element is a substance that 
has defied both analysis and synthesis. Later it was generally 
taught, and not infrequently the so-called chemical elements are 
looked upon as undecomposable substances rather than as unde- 
composed ones. Furthermore, it is quite safe to say that prac¬ 
tically no serious efforts are being made to resolve any of the 
long known elements into something simpler. The very fact 
that these substances have been placed in the table of elements, 
has drawn attention away from efforts to decompose them; 
and some of the recently reported transmutations of Bamsay 
