JANUARY 4, 1901.] 
2. €., density varies with the inverse square of 
voltivity and directly as compressibility. 
Since, then, my theory calls for a change in 
density proportional to F? and since compres- 
sional energy varies as the second power of the 
compression, my theory makes the compres- 
sional energy vary as the fourth power of the 
electric intensity. 
Dr. Franklin later says (last par.) : 
“Tf, however, the compressional energy 
were proportional to the fourth power of the 
resultant field intensity, then * * * gravitation 
would be provisionally explained.”’ 
Out of Dr. Franklin’s own mouth, therefore, 
we have it that my theory provisionally ex- 
plains gravitation. 
As regards the second point, he says: 
‘« Professor Fessenden, in his article referred 
to, speaks quite in general of the compression 
of the ether near a charged body, or ion, with- 
out localizing the distortion.”’ 
But thisis not true. I have given the precise 
and exact distribution, par. 40, where I state, 
‘(This change in density varies as the fourth 
power of the distance from the corpuscle.’’ 
I do not wish to complain, but no one cares 
to be continually misrepresented, and it is 
much to be regretted that Dr. Franklin was 
not able to note that I had covered the points 
he has criticised. 
Thirdly, Dr. Franklin says (p. 889, 1st col. 
bottom): 
‘One might therefore expect that an hy- 
pothesis as to the constitution of matter which 
clears up the nature of inertia, even pro- 
visionally, would throw some light upon the 
nature of gravitation, but it does not seem to 
be so, and Professor Fessenden must needs say 
more from his point of view before we will be 
convinced.”’ 
But this is just what my theory doesdo. As 
I have pointed out elsewhere this is one of the 
very strongest points in favor of my theory, 
and in the paper criticised I have explicitly 
stated this, as, to quote (par. 41): 
“The inertia of the atom is due to the elec- 
tromagnetic inductance of the corpuscular 
charge, and gravity is due to the change of 
density of the ether surrounding the corpus- 
cles, produced by the electrostatic stress of the 
SCIENCE. 
29 
corpuscular charge. 
a constant ratio.’’ 
Having thus answered all of Dr. Franklin’s 
objections to my theory, I must now call atten- 
tion to some very serious misstatements. 
To take the firstone. He says (p. 887, par. 2): 
‘« Professor Fessenden claims to have derived 
numerical functional relations [the italics are 
Professor Franklin’s] with the aid of his Quali- 
tative Mathematies.”’ 
Now it is very wrong to say this. If I were 
to write an article in a scientific paper, stating 
that Dr. Franklin believed that the earth was 
flat, and after stating that this was believed by 
scientists to be impossible, ‘on definite rational 
grounds,’ and inviting my readers ‘to ignore’ 
his arguments, Dr. Franklin would justly con- 
sider that he had reason for complaint. But 
he would not have so much of reason as I have, 
for whilst Dr. Franklin has never, to my knowl- 
edge, published his opinions on this matter, I 
have, in no less than four papers, explicitly stated 
views which are the exact reverse of those Dr. 
Franklin attributes tome. In the very paper he 
is criticising I say (par. 5): 
“ Qualitative Mathematics, as its name signi- 
fies, is used, not for the exact determination of 
numerical values, but for the prediction and 
classification of phenomena.’’ 
I really could not put it any plainer. I do 
not see why Dr. Franklin makes his statement. 
He cannot point to any statement or any work 
which I have ever done in which I have tried to 
deduce numerical relations by means of quali- 
tative mathematics. 
So far from this being the case, I have fre- 
quently stated exactly the opposite. As in- 
stance the above quotation. Also in my paper 
on the ‘ Nature of Electricity and Magnetism,’ 
Phys. Rev., Jan., 1900. Also, in my paper 
in the Electrical World, of some years ago, I 
point out very specifically that this same 
numeral coefficient, which Dr. Franklin says I 
have overlooked, cannot be determined by 
Qualitative Mathematics, and I then go on to 
point out,that since, this coefficient being of 
zero quality, we can always make it equal to 
unity by choosing suitable units, it is a matter 
of no consequence in discussing the nature of 
phenomena, however important it is as regards 
Mass and gravity thus bear 
