362 
NATURE 
[ FEBRUARY 14, 1907 
American Association for the Advancement of Science. 
Here we find expounded with rare clearness and 
happy illustration the essential principles of multiple 
algebra. We can imagine many aspiring mathe- 
maticians getting from this article a strong impulse 
towards the study of a subject the fundamental prin- 
ciples of which are at times almost intuitive, but the 
working out of which in detail is full of difficulties 
and pitfalls to trap the unwary. 
Under the heading of ‘The Electromagnetic 
Theory of Light ’’ there are five papers, all important 
contributions. They show the sufficiency of the 
electromagnetic theory to explain dispersion and 
double refraction, whereas the elastic solid theory 
of Green could not be reconciled with experimental 
facts. The elastic theory was, mathematically speak- 
ing, rescued from its distressed condition by Kelvin 
when he imagined the contractile ether; and in re- 
gard to this Gibbs points out that, although it 
explains many phenomena as simply as the electro- 
magnetic theory, it fails to give a_ satisfactory 
explanation of dispersion. ; 
Finally, there are six miscellaneous papers, partly 
reviews and biographical notices. The closing sen- 
tence of his notice of Clausius, in which reference is 
made to the great number of papers published by 
the eminent German, might by a slight modification 
be applied to himself. 
“Such work as that of [Gibbs] is not measured 
by counting titles or pages. His true monument lies 
not on the shelves of libraries, but in the thoughts 
of men, and in the history of more than one science.’ 
The papers have been edited with great care by 
Henry Andrews Bumstead and Ralph Gibbs van 
Name, and the former, in the biographical notice 
prefixed, discusses with knowledge the scientific work 
done by Willard Gibbs, and gives a clear-cut picture 
of the man himself. A portrait forms the frontispiece 
to vol. i. CRGaK 
TECHNOLOGY OF SOAPS AND CANDLES. 
Modern Soaps, Candles, and Glycerin. By L. L. 
Lamborn. Pp. xx+688. (New York: D. Van 
Nostrand Company; London: Crosby Lockwood 
and Son, 1906.) Price 30s. net. 
HIS is a work intended primarily for the soap 
manufacturer, and more especially for the 
American beginner in the art and craft of soap- 
making. The author finds, he tells us, that the in- 
dustry has hitherto been indebted for its technical 
literature to those who can write, but have little worth 
telling. To remedy this state of things he, a prac- 
tical man, to practical men sends forth the present 
volume. 
On the whole the effort is a successful one, though 
the book has defects. Let us summarise these at 
the outset. Heavy both in style and in avoirdupois, 
and printed on glazed paper that is very trying to 
the eyesight, the work is by no means an attractive 
one to read. There is much tedious repetition, and 
NO. 1946, VOL. 75] 
an unnecessary amount of technical slang is 
employed. For example, on p. 340 we are directed 
to “kill the rosin as already described, but leave the 
soap open on salt alone, with entire absence of 
strength.”” The book is quite “* practical’? enough 
to dispense with kettle-rroom jargon. Generally, it 
suffers from excessive verbiage; the author has a 
tendency to round his subject as well as 
upon it. 
Now let us see what there is of value in the bool. 
The various operations of soap manufacture are fully 
described, about two-thirds of the available space 
being devoted to this branch of the subject. Two 
introductory chapters outline the history and prin- 
ciples of soap-making; then come three others, deal- 
ing respectively with the raw materials, their purifi- 
cation, and their chemical characters; these are 
followed by one describing the mechanical equipment 
of a soap factory, and next by the sections which dis- 
course of the various kinds of soap and the processes 
involved in their production, The treatment is 
eminently practical, and, so far as the reviewer can 
judge, entirely trustworthy. Many useful tables. 
formule, and recipes are embodied in the text; a 
good section on essential oils and soap perfumery is 
interpolated; and a large number of illustrations of 
apparatus are included. These last are, naturally, 
figures of American machinery almost exclusively: 
they constitute quite a feature of the worls. 
In connection with ‘* medicated’? soaps, the author 
is sceptical about any appreciable curative effect being 
rightly attributable to the medicament or disinfectant 
incorporated with the soap. The proportion of active 
ingredient is often very small, and under ordinary 
conditions of use the time of contact with the skin 
+s but short, so that the scepticism is probably 
justified. Such curative property as the soaps may 
possess is, the author thinks, inherent in the detergent 
itself; the remedial value lies in the mechanical action 
of cleansing rather than in any specific bactericidal 
or antiseptic effect of the incorporated substance. 
In the section dealing with the manufacture of 
candles there are two points of special interest. One 
of these relates to a long-standing problem of chemical 
technology, namely, how best to utilise the by-product 
oleic acid as a source of candle material. This acid 
forms a large proportion of ordinary fats, but, being 
a liquid, is not suited for the production of candles. 
It is possible, however, to convert the oleic acid into 
solid substances (elaidic acid, hydroxystearie acid), 
which can be so used; but until recently the expense 
and the smallness of the yield have prevented the 
satisfactory utilisation of the by-product in this way. 
The author outlines the latest modification of the 
process for transforming oleic acid into hydroxy- 
stearic acid; it is asserted that from 85 per cent. to 
95 per cent. of the former can now be obtained as 
the solid product, instead of only 30 per cent. as 
previously produced. Sulphostearic acid and stearo- 
lactone are obtained by dissolving the oleic acid in 
petroleum and treating the solution with strong 
sulphuric acid; the first gives hydroxystearic acid on 
hydrolysis with steam; the stearolactone is re-con- 
write 
