NATURE 
JANuARY 14, 1904] 243 
| 
vania are included. The treatment of the mother- | English Allxali Acts, too, although regarded as 
liquors for the recovery of potassium salts leads then to | ‘‘ Draconian,”’ are nevertheless commended. Indeed, 
the next chapter, in which the production of potassium 
chloride and sulphate is described. 
Here in this second chapter we have an instance, 
graphically told, of the kaleidoscopic changes which 
an unexpected discovery may sometimes bring upon a 
seemingly permanent industry. Balard, the discoverer 
of bromine, had devoted some years of his life to the 
creation of a new manufacture—the recovery of 
petassium salts from sea-water, to wit—for the benefit 
of his beloved Provence. The methods were worked 
out satisfactorily, an influential company was formed, 
and everything promised a great commercial success. 
Ia fact, the products were already on the market when 
news came of the discovery, in the ‘* dead lands ’’ round 
the little Prussian town of Stassftirt, of those great | 
deposits of potassium and magnesium salts which have 
since made the district famous. Down went the price 
of potassium chloride to less than one-half its former 
figure, and with the fall vanished the new French 
industry. It did not, indeed, succumb without a brave 
little struggle, and during this the processes were so 
much improved that, as the author apparently thinks, 
a fortunate chance might even now bring them to the 
front again. But at that time, at any rate, the fight 
was hopeless, and the works round Stassfiirt were 
speedily left victors in the markets which they have 
ever since controlled. 
Potassium carbonate from vegetable sources is next | 
treated of. The burning of plants for the sake of their 
“potashes”’ the author regards as a barbarous and 
brutal kind of industry. It appears that the march of 
civilisation in the United States is shown by the 
gradual shifting of the centres where potassium 
carbonate is prepared—a remark which recalls, though 
antithetically, the epigram about a nation’s progress 
being measured by the sulphuric acid it requires. It is 
interesting to note that although at one time potash 
was largely displaced by soda in manufacturing pro- 
cesses, yet now, thanks to agricultural requirements, 
the demand for potassium salts is greater than ever. 
Iodine and bromine form the subject of chapter iv., 
and are clearly if somewhat shortly described. The 
next twelve chapters are occupied chiefly with the soda 
industry. The ammonia-soda process is lucidly dealt 
with in two short chapters, and a considerable 
amount of space is devoted to the Leblanc process. 
The author justifies this on the ground that the latter 
method has still some vitality left, and is always cap- 
able of making progress. Much of the description is 
certainly interesting, especially that giving personal 
details of the discoverer, his successes, and his vicissi- 
tudes. But the interest is mainly historical. Even in 
this country the battle of the ammonia versus the 
Leblanc process can hardly be said to be so doubtful in 
its issue as the author seems to think it. The electro- 
lytic method is barely mentioned; a little more space 
might well have been devoted to it. 
In any adequate account of the alkali industry this 
country must figure largely, and such names as those 
of Gossage, Hargreaves, Mactear, Muspratt, 
NO. 1785, VOL. 69] 
the author is inclined to attribute much of the progress 
which the alkali manufacture has made in Great 
| Britain to the fact that the makers were forced to 
collect their hydrochloric acid instead of distributing it 
broadcast over the countryside. It is, of course, an old 
story, but it will bear recalling, how, in spite of the 
great clamour raised, the alkali manufacturers were 
compelled to take those steps which eventually proved 
to be their economic salvation. The rejected stone 
became the headstone of the corner; the troublesome 
by-product presently supported the whole industry. 
Chlorine, bleaching-powder, and chlorates are dealt 
with in the last five chapters. There is nothing 
particularly new, but the descriptions include the 
standard processes, such as those of Deacon, Weldon, 
Dunlop, Mond, and Péchiney, and give a good general 
idea of this branch of chemical industry. 
The work contains a number of illustrations, but 
lacks an index. It will be useful to those who require 
something more complete than a general text-book 
description, but less extensive than Lunge’s standard 
treatise. C. Smmmonps. 
THE ELEMENTS OF ELECTRICAL 
ENGINEERING. 
Electricity and Magnetism. By C. E. Ashford, M.A. 
(London: Edward Arnold, n.d.) Price 3s. 6d. 
Electric and Magnetic Circuits. By Ellis H. Crapper, 
M.I.E.E. (London: Edward Arnold, n.d.) Price 
Ios. 6d. 
Text-book of Electrical Machinery. Vol. i. 
Electric, Magnetic and Electrostatic Circuits. By 
H. J. Ryan, H. H. Norris, and G. L. Hoxie. (New 
York: John Wiley and Sons; London: Chapman 
and Hall, Ltd., 1903.) Price 2.50 dollars. 
HE best method of training electrical engineers 
will probably remain a subject of discussion so 
long as the profession continues to be a profitable one. 
Whether recourse should be had to the factory or to 
the technical college; whether a combination of these 
two is desirable or necessary, and if so, in what 
manner they should be combined; and whether the 
course at the technical college should be entirely by 
lecture and experiment, or should make free use of 
that royal road to excellence, the text-book; these and 
kindred questions will always be discussed and will 
never be settled. Whilst the-discussion goes on the 
writers of text-books continue to flourish until the 
difficulty of deciding whether to have recourse to text- 
books or not is overshadowed by the greater difficulty 
of deciding which would be the most profitable to read. 
The three books before us illustrate how the budding 
electrical engineer may be caught when he is yet fresh 
in kxnickerbockers and led by easy steps to a complete 
mastery of his profession. Mr. Ashford’s ‘ Electricity 
and Magnetism’’ is a_ school-book; it starts by 
assuming that the pupil has no knowledge of the sub- 
A 
| ject at all, and, leading him by a path of experimental 
and | 
Mond receive due mention in the present work. The | Mr. Crapper’s more advanced treatise. 
inquiry, ends by leaving him well fitted to begin on 
This read, 
