1888.] Prof. Tait’s Reply to Prof. Boltzmann. 145 
all investigators except Meyer have fallen into the same trap. 
.Meanwhile the calculation with which Professor Boltzmann has 
furnished me gives an excellent example of his style, for it is 
altogether unnecessarily tedious. And it seems to contain two 
gigantic errors which, however, compensate one another. For his 
integrand contains the factor Here / is a signless quantity, 
and the limits show that x is always positive and p always negative. 
As written, therefore, the integral is infinite, though in the result it 
is made to come out finite. The object of the paragraphs 1 and 2, 
which immediately follow, is unintelligible to me. The former 
seems to suggest the use of an unsound method, the latter has no 
discoverable bearing on anything that I have written. Prof. 
Boltzmann has also afforded an idea of the value which he himself 
attaches to the terrific array of symbols in the 95 pages of his 
1881 paper (to which he refers me) by now allowing that he is 
not prepared to assert that any one of three determinations of 
the coefficient of viscosity which he quotes (mine, or rather his own, 
being among them) is to be preferred to the others ! 
Fourth. Prof. Boltzmann refers to my remarks on Mr Burbury’s 
assertion that a single particle, with which they can collide, would 
reduce to the special state a group of non-colliding particles. Prof. 
Boltzmann signified his belief in the truth of this proposition ' and 
in answer I showed that (were it true) seons would be required for 
the process, even if that were limited to a single cubic inch of gas. 
He now calls this an “ entirely new question ” and will not “ prolong 
the controversy by its discussion.” I do no see that, so far at least 
as the “ controversy ” is concerned, it is any newer than the rest. 
It is contained in the first instalment of his attack. Why then 
should he now desert it ? But Prof. Boltzmann, in thus leaving the 
subject, takes a step well calculated to prolong the discussion, for 
he represents me as speaking of the instantaneous reversal of the 
motions of all the particles, whereas my argument was specially 
based on the revei'sal of the motion of the single stranger alone, a 
contingency which might possibly occur by collision even with a 
particle of the gas, certainly by collision with the containing vessel. 
There is a common proverb, “ All roads lead to Home.” It seems 
it ought now to be amended by the addition, “whether you go 
backwards or forwards along them.” 
VOL. XV. 26/6/88 
K 
