INSTRUMENTS AND METHODS OF RESEARCH. Ill 
as yet the increase of our powers of perception along other 
lines than chiefly those of sight. No one can foretell the 
future possibilities in these directions. 
The doctrine of evolution teaches the result of long-dis- 
continued use of any particular organ, and has familiarized 
us with the wonderful achievements of Nature brought about 
by sustained and continued effort along some definite direc- 
tion. Both the physical and the psychic condition of the 
observer requires their highest and healthiest development 
to insure not only the best results with the ever-increasing 
accuracy or precision required by the steady advance of 
knowledge, but also to bring about that round- or broad- 
mindedness needed for the proper interpretation of the re- 
sults observed. 
The Mathematical Instruments of Research. 
A good-sized chapter might be written on the “Mathemati- 
cal Instruments or Tools of Research.” The predominating 
tendency of resolving or expressing every natural phenome- 
non periodic or otherwise — by a Bessel or a Fourier series 
or by spherical harmonic functions has brought about at 
times, especially in geophysical and cosmical phenomena, if 
not direct misapplications, at least misinterpretations of the 
meaning and value of the coefficients derived. 
Like a ceitam class of naturalists, we also may have 
laid ourselves open to the opprobrious term of “Nature- 
Fakir, and instead of clarifying the situation our calcula- 
tions may have actually contributed instead to “befog” it. 
Frequently by the purely mathematical process there have 
been eliminated, in the attempt to represent a more or less 
irregularly occurring natural phenomenon by a smoothly 
flowing function, the very things of chief and permanent 
interest. The normal or average diurnal temperature curve, 
for example, or a uniform magnetic distribution over land* 
so as to yield perfectly regular lines of equal magnetic decli- 
nation, never occur in Nature. There is thus being im- 
pressed upon us more and more forcibly the fact that what 
17— Bull. Phil. Soc., Wash., Vol. 15. 
