78 
NA POLE 
[May 25, 1899 
Macmillan and Gavin Dalzell’s construction of a practical 
rear-driver, the appearance of the original Dunlop pneu- 
matic tyre with outer cover cemented to the rim, while 
free-pedals are merely referred to as incidental accom- 
paniments of automatic brakes. Dr. Bourlet’s history of 
the introduction of pneumatic tyres reads like a bur- 
lesque :— 
“|. The first pneumatic tyres were very timid at- 
tempts, and at the best only suitable for racing tracks. .. . 
The single tube tyres, Clincher, Boothroyd, and others 
then became popular, and were a little more trustworthy. 
. . . It was not until Michelin put on the market his de- 
tachable tyre that pneumatic tyres entered the domain 
of practical cycling mechanics. . . . Six months later the 
Dunlop Company exhibited a detachable tyre. . . .” 
Again, in the purely descriptive portions of the book 
many important developments of the last three or four 
years are entirely unnoticed ; to wit, Lloyd’s cross-roller 
gear, the Fleuss and Trench tubeless tyres, jointless 
hollow rims, short-pitch roller chains, the Bowden brake 
transmitting mechanism; in fact, the book is at the 
date of its publication several years behind the times, as 
far as the bicycle in England is concerned. 
The discussion of the various points of construction 
are very interesting and instructive ; but the conclusions 
drawn by the author are in many cases diametrically 
opposed to opinions widely held on this side of the 
Channel. The author has proved that, for ease of steering, 
the frame of a good bicycle should beas short as possible ; 
the frame with extended wheel-base “était donc détest- 
able ; il manquait d’ailleurs de rigidité.” The frame of 
the Pedersen bicycle, weighing less than 20 lbs. com- 
plete, receives most praise ; but the author would im- 
prove it by substituting pin-joints for the rigid lugs. Mr. 
Mushing’s analysis in the Centaur Company’s catalogue 
of the weight of a bicycle equipped as a heavy roadster 
and as a road racer (total weights 36 Ibs. and 25 lbs. 
respectively, weight of frame and front forks in each 
case 7 lbs. 15 oz.) might modify the author’s opinion on 
this point. 
In chains, a retrograde movement was effected when, 
in 1895, English makers returned to the detestable block 
chains, “un peu modifiées, il est vrai, mais toujours aussi 
mauvaises.” Now, whatever be the merits of the 1899 
roller chains, the old inch-pitch roller chains were much 
worse than the block chains which superseded them. 
Has the author compared, say,a Hans Renold block 
chain with the roller chains made prior to 1895? The 
type of roller chain held up for admiration is that with 
each sleeve split at the middle, a half-sleeve being made 
as a solid internal projection from each inner side-plate. 
This construction is thoroughly bad, and no chain made 
in this way is durable, as some chain-makers have found 
to their cost. 
A great number of two-speed gears are described, 
none of which have been sold to any extent in England, 
while the few two-speed gears known here are not 
referred to. This chapter is therefore of interest mainly 
to the mechanician and the designer. 
As a practical guide to the cyclist in choosing a new 
machine, the book will be of most service in France, but 
of little or no value here. ASS: 
NO. 1543, VOL. 60] 
OUR BOOK SHELF. 
The Spirit of Organic Chemistry. By Arthur Lachman, 
B.S., Ph.D. With an Introduction by Paul C. Freer, 
M.D., Ph.D. Pp. ix+ 229. (New York: The Mac- 
millan Company. London: Macmillan and Co., Ltd., 
1899.) : 
THE title of the book, if it conveys a definite idea, scarcely 
explains the contents. The preface, however, sets forth 
the various objects which the book is intended to ac- 
complish. Its main purpose, we are told, is to supplement 
the text-book and to introduce the student to the current 
literature of the subject, from which it is to be inferred 
that he will be equipped with a sufficient knowledge of 
present problems to follow contemporary research. 
The volume consists in reality of a series of essays on 
subjects which have at one time or another engaged the 
attention of chemists. It is divided into chapters, the 
heading of each furnishing the text for a discourse on 
some prominent theory or classical investigation. ‘ The 
constitution of acetoacetic ether” leads up to an account 
of tautomerism. The constitution of the sugars, of maleic 
and fumaric acids, of the oximes and of the diazobenzene 
compounds, involve a series of dissertations on stereo- 
chemical problems ; whilst the chapters on uric acid and 
the constitution of rosaniline record the development of 
certain branches of synthetic chemistry. An essay on 
the constitution of benzene, and a brief history of 
“Perkin’s reaction,” complete the series. The subjects 
are not by any means exhaustively treated ; but they are 
presented in an easily readable form, and controversial 
matters are handled in a judicial spirit. 
Whether these few essays will enable the student to 
follow current literature is another question. A great 
amount of organic research is now busy with the con- 
stitution of the terpenes, the camphors, the alkaloids, the 
artificial and natural colouring matters, and many other 
subjects of which no word is said. Moreover, several of 
the subjects discussed have passed into history. Still, 
there will doubtless be many to whom the volume should 
prove interesting and profitable reading. 
The introductory chapter does not add substantially to 
the value of the book. Its rather high-sounding phrases 
convey little real information, and the historical references 
are too brief to be intelligible to any one ignorant of the 
history of the science. Jaeba Ge 
Elementary Physics and Chemistry. First Stage. By 
Prof. R. A. Gregory and A. T. Simmons, B.Sc. 
Pp. vill + 150. (London: Macmillan and Co., 1899.) 
THE importance of experimental science teaching in 
elementary schools is being more and more recognised 
by the Education Department every year. This tendency 
is seen in the course of elementary physics and chemistry 
for the upper standards, which was introduced into the 
Elementary Education Code for 1898. To meet the 
want thus created is the purpose of the present book, 
covering the first of the three parts into which the 
syllabus is divided. The plan of the book is admirable, 
and though the division of each lesson into ‘what to 
do,” “reading lesson,” and things “to be remembered,” 
involves a certain amount of repetition, there will be 
compensation to young students in the resulting clear- 
ness. Matters are so arranged that the lessons are suit- 
able for classes in which each pupil can perform the 
experiments for himself, or for those in which they can 
be made by the teacher alone. In their anxiety to 
secure a logical sequence of thoughts, the authors have 
included a few experiments, the results of which we 
think might have been taken for granted ; but, apart 
from this, the book seems well adapted for beginners in 
science. The clear and simple language, combined with 
a large number of excellent illustrations, can surely 
leave no doubt in the mind of the dullest pupil as to the 
ideas which are intended to be conveyed. 
