172 NATURE 
[ DECEMBER 20, 1906 
ENGINEERING DESIGN AND DRAWING. 
{1) Machine Design. By Prof. Albert W. Smith and 
G. H. Marx. Pp. viii+369. (New York: John 
Wiley and Sons; London: Chapman and Hall, 
Ltd., 1905.) Price 12s. 6d, net. 
(2) Elements of Mechanical Drawing. By A. A. Tits- 
worth. Pp. v+130. (New York: John Wiley and 
Sons; London: Chapman and Hall, Ltd., 1906.) 
Price 5s. 6d. net. 
HE authors of this text-book have wisely de- 
parted somewhat from the usual practice fol- 
lowed in books on machine design, and have devoted 
the first five chapters to discussions of the general prin- 
ciples of kinematics which underlie the design of all 
classes of machinery. These chapters, in fact, deal with 
subjects such as constrainment of motion, relative 
motion, linkages, linear and angular velocity dia- 
grams, &c., which the student usually finds only fully 
and clearly discussed in such works as Kennedy’s 
‘“Mechanics of Machinery.’’ In the sixth chapter 
the question of the proportions of machine parts as 
dictated by stress is taken up, and rules are given 
for the working stresses which must be adopted under 
any given set of conditions. 
Fastenings, including rivets and bolts and nuts, are 
then considered. The authors rightly point out that 
the dimensions of the rivets which would be necessary 
in order to secure a joint of absolutely uniform 
strength are, in the case of lap joints, usually too 
large for practical convenience, and that, therefore, a 
compromise has to be effected; but surely the tables 
on pp. 94 and 95 are carried to an excess as regards 
thickness of plates, as no one would in practice 
think of using such joints for plates one inch or more 
in thickness. In dealing with bolts and nuts, natur- 
ally only the United States standard threads are em- 
ployed, and in this chapter the results of some interest- 
ing experiments on the design of bolts for shock are 
given; it was shown that bolts with a hole drilled out 
in the centre through the unscrewed part, so as to 
give them a uniform cross-sectional area from end 
to end, were much stronger against shock than the 
original solid bolts. 
The design of axles and shafts and of their bear- 
ings, including the modern ball and roller bearings, 
is very fully treated in several chapters; and then 
follow details of the design of couplings, both per- 
manent and frictional, and a complete explanation 
of the theory of the transmission of power by belts 
and of the necessary calculations in order to settle 
the dimensions of belt required in any given case. 
Fly-wheels and toothed wheel gearing are taken up 
in the next two chapters, the proper shape of gear 
teeth and their strength being dealt with in a very 
thorough manner. In the concluding chapter a 
branch of machine design usually much neglected 
in text-books is discussed, namely, the proportions 
and best shapes for machine frames. 
The authors are to be congratulated on the fact 
that they have avoided crowding their illustrations 
with minute details, and, as a result, all the figures 
are clear, and the important points in the design 
which they are intended to illustrate are easily 
NO. 1938, VOL. 75] 
(1) 
followed. The book 
should prove a useful text-book 
for engineering students in their first and second 
years’ courses in machine design. 
(2) This book is divided into two parts. In the first 
part, for beginners, the various drawing instruments in 
common use are described, and a series of exercises 
is given to illustrate the use of each of the instru- 
ments. The rest of this section is devoted to ex- 
amples in simple projection, to intersections of solids, 
and development of surfaces. Part ii., for more ad- 
vanced students, comprises problems in descriptive 
geometry, isometric projection, oblique projection, 
shadows, and perspective work, and concludes with a 
series of problems. The author has dealt with a 
branch of engineering drawing which is more com- 
monly denoted by the name of geometrical drawing. 
The volume will form a useful text-book for students 
in engineering colleges during the first year of their 
course. Tee 
OUR BOOK SHELF. 
Das Kloster Kumbum in Tibet. By Wilhelm Filchner. 
Pp. vi+164; with maps, plans, and numerous 
plates. (Berlin: S. Mittler und Sohn, 1906.) Price 
8 marks. 
One of the most popular fanes of Lamaist pilgrimage 
is the great golden-roofed temple of Kumbum, about 
half-way between Lhasa and Pekin, in the neigh- 
bourhood of the Koko Nor Lake, on the border of 
nee It marks the sacred spot where was born 
in 1356 a.D. the reforming Lama and canonised 
saint Tsong-Khapa, who founded the now predomin- 
ant yellow-cap sect which wields the temporal power. 
On the sacred spot itself, within the precincts of the 
temple, stands an old tree which is believed to have 
sprung miraculously from one of the saint’s hairs. 
It is locally known as the ‘‘ white sandalwood tree,”’ 
and both its leaves and barlx are held in great venera- 
tion as exhibiting on their surface images of the 
holy man. M. Huc, in his lively description of his 
visit to this sanctuary and his interview with its 
“Living Buddha,’ half a century ago, declared that 
he himself saw the images on the leaves, and he 
attributed this extraordinary phenomenon to the 
devilry of the priests. Since Huc’s time the place 
has been many times visited and described by Euro- 
peans, lying as it does within that portion of eastern 
Tibet which has been annexed by China, and thus 
much more easily accessible than the ‘‘ Forbidden 
Land ”’ of the Lhasa Lamas. 
By far the best and fullest of these descriptions has 
hitherto been that by Mr. Rockhill, the present United 
States Ambassador at Pekin. Mr. Rockhill found 
that the alleged images on the leaves and bark were 
a delusion, and that they only appeared to those 
votaries who had firm belief, whilst the faithless could 
distinguish nothing extraordinary on them. The 
specimens of the leaves and bark collected by Mr. 
Rockhill were identified by Mr. Hemsley, of Kew, as 
those of Syringa villosa, Vahl.; whilst Dr. Kanitz, of 
St. Petersburg, made the tree out to be Ligustrina 
amurensis (Nature, April, 1896, pp. 534 and 556). 
Lieut. Filchner now gives us a handsome monograph 
on Kumbum, its temple, tree, and priests, as the result 
of his expedition there in 1903-1905, by way 
of Shanghai. Mr. Filchner started commendably 
equipped with an intimate knowledge of the literature 
of his subject, and has produced a record of per- 
manent value, embodying a good deal of new re- 
