562 
NATURE 
[AeRIL 14, 1904 
He seems to think it easy to study some of those 
irreversible changes which even the greatest of mathe- 
matical physicists have been afraid of, and it is my 
ungrateful duty to say that he is so ill equipped for the 
study that he does not comprehend the elementary 
principles of thermodynamics. Even in the last page 
of this book he states that thermodynamics ‘‘ is per- | 
haps the most slippery branch of science there is.” 
He does not seem to know that in the books con- 
demned by him there is an exact study of some irre- 
versible processes. such as the wiredrawing of steam, 
and that the t@ diagram lends itself to the study of 
another irreversible process, the efflux of steam from an 
orifice. 
I take it that this mental phenomenon js not, after 
all, curious; it is often exhibited when men of 
great individuality refuse to take the usual point of 
view, refuse to use words in the exact sense in which 
other people use them, and create a scientific language 
of their own which prevents mutual understanding 
with other people. Mr. Swinburne shows that he has 
not been able to study the subject from the usual 
scientific point of view; he has a view of his own 
much like that of David Deans in religious matters. 
He says :—‘ So far as I am aware there is not any 
work on the steam- or gas-engine in this country that 
gives a correct definition of entropy.” Throughout 
the book he is everywhere severe upon other writers. 
““ Most treatises on physics, English and foreign, con- 
tain incorrect definitions of entropy.’’ We wonder 
whether any English writer would be particularly 
pleased in being told that his treatise was held by Mr. 
‘Swinburne to be one of the exceptions to this sweep- 
ing indictment. But at p. 119 he goes further. 
‘“‘T know of no writer who has tried to give any sort 
of explanation of what is meant by entropy, except 
that it is the quantity factor of heat, which is ob- 
viously nonsense.”’ ‘‘ As a young man, I tried to read 
thermodynamics, but I always came up against 
entropy as a brick wall that stopped my further pro- 
gress.” Of course it was not the simple idea of 
entropy with which we try to make all students 
familiar which stopped his progress. It was Mr. 
Swinburne’s own idea, and any persevering person 
who manages to get through this book will say that 
this idea of entropy (or these ideas, for there are many 
and inconsistent) has not only stopped Mr. Swin- 
burne’s progress, but may send any ordinary man into 
a lunatic asylum. : 7 
He has not only a view of his own about thermo- 
dynamics, but a painful examination shows that he 
has several points of view of his own. When he 
‘occupies one of these his statements sound quite 
orthodox, but presently the reader finds that he has 
completely changed his point of view, and it is ex- 
ceedingly difficult for even a painstaking reviewer to 
find out what particular kind of mistake he is making. 
He is dealing with a mathematical subject, and yet he 
will not keep to one definition of any of the quantities 
he is dealing with. Because of certain old terms 
such as “‘ latent heat ”’ being in use, he seems to think 
that in thermodynamics we do not use the word heat 
in a definite sense, and from all that the ordinary 
writers of treatises say he is not sure that to them 
external work is not heat or chemical energy or elec- 
tron-flights or the energy of pedesis (pp. 116-117). 
He himself takes great liberties with the word, and it 
is quite evident that he believes heat to be something 
not yet defined and not yet measurable. He some. 
times uses the word correctly as meaning heat re- 
ceived by the working substance; but mostly he thinks. 
of heat as something in the working substance, and 
in the majority of such cases what he calls heat is 
NO. 1798, VOL. 69 | 
what we should call ‘‘ intrinsic or internal energy ”’ 
(see pp. 15, 16 and 32, where he uses ‘‘ heat’? and 
“internal energy ’’ indifferently). 
Thus, at p. 124, after some vague phrases which 
he seems to regard as a definition, he says, ‘‘ this 
definition of heat includes the heat that makes things 
hot, and locomotive heat in general, and it also in- 
cludes ‘latent heat’ at constant volume, but only part 
of any misnamed ‘latent heat’ that includes any 
form of external work. It includes latent heat of 
fusion, of vaporisation apart from external work, 
and of allotropic modification. What is most 
heterodox is that it includes chemical energy.’’ It is 
hardly believable that in a dynamical illustration (p. 
108) he should imagine the momentum of a system 
of two colliding bodies to be increased by the collision, 
in opposition to the most fundamental, most elemen- 
tary principle of mechanics. Possibly, as in the case 
of entropy, he attaches a novel meaning to such a 
term as momentum.- Men who use the poundal will 
be interested in a statement on p. 57:—‘‘ But as we 
have the *foot-pound and I think, the poundal, as 
units of energy. . .’’ I mention only a few of these 
curious things without comment, because any adequate 
comment would almost seem to be a personal insult. 
He possesses the power of persuasively stating or 
implying as a major premiss some general notion of 
his own and then drawing the conclusions which he 
wants to draw. For example (p. 136), ‘‘ The fact that 
certain units in thermodynamics have no names goes 
to show that the science is not fully developed. 
Measurement is an essential in science.’’? In the first 
part of this he implies the great major :—a science is 
not fully developed (as no science is fully developed, he 
means ‘‘is badly developed ’’) unless the units of the 
quantities dealt with have names. Is dynamics badly 
developed? And is there a name for the fundamental 
unit of all, the unit of momentum? In the second 
part he implies that there is no measurement if there 
are no names for the units. Is there no measure- 
ment? Is there not the most accurate measurement of 
momentum? Is mathematics, is Euclidean geometry 
a science? What are Euclid’s names for the units of 
length or area or volume? Is astronomy a science? 
What is the name for the units of force or momentum 
used by Newton? He immediately proceeds to give 
as an example that there'is no name for differences of 
temperature according to’ the absolute Kelvin scale. 
I think that hé- does not mean the absolute scale of 
1848, because that scale is only of historical import- 
ance; he probably means the perfect gas scale invented 
by Clausius' in 1850,’ which Kelvin showed in 1854: to 
be independent of ‘the nature of the working substance 
—well, why can he not be satisfied with’ the name 
“degree ?’? ‘Surely he might have tried to suggest a 
better name. ; 
The name Rank is used by many English speaking 
people for the British unit of entropy, and it even 
appears sometithes in examination papers; it is most 
appropriate. But of ‘course, it would be out of the 
question to expect Mr. Swinburne to use an existing 
name, so he wishes to have’ the' word Claus used for 
the British unit of entropy. ~ Rankine used this unit 
always; it is impossible to ‘imagine that Clausius ever 
did, or that any person not an Anglo-Saxon ever will. 
This may merely indicate love for the foreigner. 
Rankine, Cotterill, Ewing and others have given great 
pains to perfecting tables of the properties of steam. 
I know that my students and I spent some months on 
tables that I myself have published. But the only 
tables of which Mr. Swinburne makes mention are 
certain American tables which are obviously incorrect 
in very important particulars. Reeve’s tables are 
certainly elaborate enough, ‘but every one of the 789 
