270 
NATURE 
[Juty 17, 1902 
curve of speed plotted on a time base. The author 
believes that this curve exhibits the kinematic action of 
the machine more clearly and directly than any other 
form of diagram. 
Beginning with the composition and resolution of 
velocities, it is shown how the constraints of slides, 
pivots and rigidly connected points affect the ordinary 
rules for vectors, and one or two simple special rules are 
established. These are applied systematically to selected 
mechanisms such as pruning shears, quick return 
motions, direct-acting and oscillating cylinder engines, 
epicyclic trains of wheels, the pilgrim-step motion, &c., 
until the reader becomes quite familiar with the process. 
No attempt is made to give more than a cursory and 
very limited account of the plane motions of mechanisms, 
consequently many important theorems and constructions 
of a general nature find no place. Simple harmonic 
motions, and harmonic analysis, often so useful, are not 
considered. Acceleration is only incidentally referred 
to in showing how an acceleration-time curve can be 
determined graphically from a velocity-time curve. The 
author has evidently imposed severe restrictions as to 
the amount of ground to be covered. But so far as the 
subject is dealt with, the methods and demonstrations 
are very clear and convincing, and the diagrams are 
well drawn and beautifully printed. 
Spiderland. By Rose Haig Thomas. Pp. vili + 227. 
(London: Grant Richards, 1902.) Price 55. 
THIS is a charming little book, based on the authoress’s 
original observations on a variety of animals and plants, 
and cast into a poetic form likely to interest children in 
natural history. It is dedicated as follows :—“To my 
Son, whose wondering child-eyes first taught me to look 
deeper into the workings of Nature, and to all the Children 
I know and shall never know, I dedicate these simple 
tales.’ As we remarked when reviewing elsewhere the 
first edition, printed for the author in 1898, which com- 
prised only the first twelve tales, whereas twelve more 
are added inthe present edition, the book reminds us of 
the “ Episodes of Insect Life,” on the one hand, and Mrs. 
Gatty’s ‘‘ Parables from Nature” on the other. The mode 
of treatment resembles that of the former book, and the 
general style the latter. A great variety of subjects are 
dealt with, and only one or two of the stories relate to 
spiders ; among others, we note such titles as “ The Tree 
Frogs,” “Pistil the Peace-maker” (a more elegant set- 
ting of the old fable of the “Stomach and the Limbs”) ; 
“ Thomisa Citrina, the Robber-Mother” ; ““ The Wedding 
of the Fly Ophrys” ; “The Green Caterpillar” (a study 
somewhat resembling one of Mrs. Gatty’s, but dealing 
with a more mournful phase of caterpillar life, an 
ichneumoned caterpillar) ; ““Hymen, the Worker Ant” ; 
“Nimble Nat, the Gay Grasshopper”; “Cocky: a 
London Love-Tale” (sparrows) ; ‘‘ The Romance of the 
Water Beetle” ; ‘The Lemming,” &c. The remarks on 
the lemming are interesting, and will be new to many 
readers. Here and there we meet with a trifling over- 
sight ; the authoress has travelled in France and Norway, 
and has forgotten to note that processionary caterpillars 
are not British ; and the auditory organs (hardly “ears ”) 
of grasshoppers are situated, not in the hind legs, but in 
the front legs. 
Children are easily interested in natural history and 
insect life ; and a poetical view of some of its phases, 
such as Mrs. Thomas has here given, is likely to prove 
more attractive to them than a purely didactic book, 
like “ Uncle Philip’s Conversations with Children,” which 
was almost the first book on natural history read to the 
present writer in his childhood. Naturally, the stories 
written by Mrs. Thomas are not all of equal merit ; but 
most of them are excellent, and we regret that our space 
will not allow us to give a sufficiently long quotation to 
afford a fair idea of the style of her book. W. F. K. 
NO. 1707, VOL. 66] 
Tuberculosts as a Disease of the Masses, and How to 
Combat It. By S. A. Knopf, M.D., of New York. 
Adapted for English use by J. M. Barbour, M.D. 
Pp. 76 ; 25 figures. (London: Rebman, Ltd., 1902.) 
Price 1s. net. 
IN plain, simple language, devoid of technicalities, Dr. 
Knopf presents an accurate account of the causes of 
tuberculosis, some details of the symptoms ofa few of its 
many phases, and indicates the chief hygienic principles 
which underlie the present-day methods of treatment. 
He emphasises the fact that tuberculosis is a con- 
tagious and therefore a preventable disease, that the 
child of a tuberculous mother is not itself necessarily 
tuberculous, although it frequently acquires the disease 
—the maternal kisses often being the channel of infec- 
tion—that man may derive the infection from animals 
and that he may in turn transmit the disease to them, 
and above all that ¢zderculosis is a curable disease. 
The author fully explains the duty of the consumptive 
to himself and to his fellows, and points out in no uncer- 
tain manner the real danger attendant upon the habit of 
spitting elsewhere than in a proper receptacle by the 
subjects of this disease. He also gives much excellent 
and useful advice with regard to the practice of calis- 
thenics by, and the inculcation of habits of cleanliness in, 
the young, and the value of fresh air and sunshine as factors 
in the prevention and cure of tuberculosis, as well as 
many suggestive hints on the home care of consumptives. 
We are not surprised to learn that this essay was. 
awarded the first prize (200/.) offered by the “ Inter- 
national Congress for the Study of the Best Way to 
Combat Tuberculosis as a Disease of the Masses,” which 
met at Berlin, and that it has already been published in 
five languages besides English. It is an excellent 
treatise, and should be in the hands of every individual, 
sick or well, who has at heart the physical welfare of his 
fellow mortals. 
The Teachers Manual of Object Lessons in Geography. 
By Vincent T. Murché. Pp. xvi + 334. (London : 
Macmillan and Co., Ltd.) Price 3s. 6d. 
How great has been the improvement in methods of 
teaching during recent years can be measured to some 
extent by a comparison of newly published books intended 
for use in public elementary schools with those in circula- 
tion twenty years ago. The old implicit reliance on the 
child’s faculty for memorising is fortunately giving place 
to an appeal to his observation and incipient reasoning 
powers. Mr. Murche’s latest addition to his already 
extensive series of books on elementary science is marked 
by his usual clearness of exposition and by that helpful- 
ness for which he is justly highly esteemed by teachers 
in elementary schools. But the bewildering miscellany 
of type, with its frequent transitions from Roman_ to 
italics and from these to Clarendon and capitals, makes 
the volume a trying one to read and raises the question 
of the possibility of such over-emphasis defeating the 
object in view. It is unfortunate that in explaining 
volcanic activity the author speaks of “ dense volumes 
of flame and smoke” which “burst out from the crater,” 
and that he instructs the teacher to explain “that ages 
ago this earth on which we live was a burning mass like 
the sun.” This seems to indicate a want of clearness as 
to the nature of smoke and burning ; it will certainly 
give the child a wrong idea. But the book should do a 
great deal to improve the teaching of geography. 
William Gilbert of Colchester: a Sketch of his Magnetic 
Philosophy. ‘sy Charles E. Benham. Pp. 96. (Col- 
chester: Benham and Co., 1902.) Price 2s. net. 
THE immediate occasion of the appearance of this little 
book is the issue to the subscribers of the Gilbert Club of 
the English translation of “De Magnete.” The author 
