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AMERICAN HOMES AND GARDENS December, 1909 
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Holiday Suggestions in Useful Books 
MAGIC STAGE ILLUSIONS AND SCIENTIFIC 
DIVERSIONS, INCLUDING TRICK PHOTOGRAPHY 
Compiled and Edited by ALBERT A. HOPKINS 
With an Introduction by Henry Ridgely Evans 
8vo. 568 Pages. 420 Illustrations. Price, $2.50, Postpaid 
©: unique work appeals to the professional and amateur 
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alike and will prove a welcome addition to any library. It is 
the acknowledged standard work on magic. ‘The illusions are 
illustrated by the highest class of engravings, and are all explained 
in detail, showing exactly how the tricks are performed. Great 
attention is paid to the exposes of large and important illusions, in 
many cases furnished by the prestidigitateurs themselves. Conjuring 
is not neglected, a selection of some of the best known of these 
tricks having been made. The work cannot fail to be of interest to 
young and old, and there is hardly anyone who is in anyway in- 
terested in either science or magic to whom it will not appeal. It is 
beautifully printed and attractively bound. An illustrated circular 
and table of contents will be sent on application. 
EXPERIMENTAL SCIENCE 
By GEORGE M. HOPKINS 
Twenty-fifth Edition, Revised and Greatly Enlarged 
1,100 Pages, over 900 Illustrations 
Lwo Octavo Volumes; Price in Cloth, $5.00; Half Morocco, 
$7.00, Postpaid 
HIS book treats on the various topics of physics in a popu- 
lar and practical way. It describes the apparatus in detail, 
and explains the experiments in full, so that teachers, 
students and others interested in physics may readily make the 
apparatus without expense, and perform the experiments without 
difficulty. The aim of the writer has been to render physical ex- 
perimentation so simple and attractive as to induce both old and 
young to engage in it for pleasure and profit. All intelligent 
persons should have at least an elementary knowledge of physics 
to enable them to understand and appreciate what is going on in = 
the world. This can be acquired by reading “Experimental Science.” As a gift from em- 
ployer to employee, from parent to child, from student to teacher, nothing could be more 
appropriate or acceptable. It is the most thoroughly illustrated work ever published on 
Experimental Physics, and its unprecedented sale shows conclusively that it is the book of 
the age for teachers, students, experimenters, and all others who desire a general knowledge 
of Physics or Natural Philosophy. Illustrated and descriptive circular on application. 
The Scientific American Boy 
By A. RUSSELL BOND 
r2mo. 320 Pages. 340 Illustrations. Price, $2.00, Postpaid. 
O™ is a story of outdoor boy life, suggesting a large 
number of diversions which, aside from affording enter- 
tainment, will stimulate in boys the creative spirit. In 
each instance complete practical instructions are given for build- 
ing the various articles. The needs of the boy camper are sup- 
plied by the directions for making tramping outfits, sleeping-bags 
and tents, also such other shelters as tree houses, straw huts, log 
cabins and caves. The winter diversions include instructions for 
making six kinds of skate sails and eight kinds of snow-shoes 
and skis, besides ice-boats, scooters, sledges, toboggans and a pe- 
culiar Swedish contrivance called a ‘“rennwolf.” Among the more 
instructive subjects covered are surveying, wigwagging, helio- 
graphing and bridge-building, in which six different kinds of 
bridges, including a simple cantilever bridge, are described. 
The. Scientific American Cyclopedia of 
Receipts, Notes and Queries 
In Three Bindings. Price, Cloth, $5; Sheep, $6; Half Morocco, rae AN 
$6.50, Post paid. Tn Tt al yer 
Ox is a careful compilation of the most useful receipts guint Sein ip ae 
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which have appeared in the Scientific American for more COFEDIA "foion 
than half a century. Over 15,000 selected formulas are here 
collected, nearly every branch of the useful arts being represented. 
It is the most complete volume on the subject of receipts ever pub- 
lished. It has been used by chemists, technologists and those un- 
familiar with the arts with equal success, and has demonstrated that 
itis a book which is useful in the laboratory, factory or home. An al- 
phabetical arrangement, with abundant cross-references, makes it an 
easy work to consult. The Appendix contains the very latest formulas 
as wellas 41 tables of weights and measures and a dictionary of chem- 
ical synonyms. A full table of contents will be sent on application. 
Home Mechanics for Amateurs 
By GEORGE M. HOPKINS, Author of “Experimental Science” 
12m0, 370 Pages, 320 Illustrations. Price, $1.50, Postpaid. 
© HE book deals with wood- working, household ornaments, metal- 
working, lathe work, metal spinning, silver working; ‘making 
model engines, boilers ‘and water motors ; making telescopes, micro- 
scopes and meteorological instruments, electrical chimes, cabinets, bells, 
night lights, dynamos and motors, electric light, and an electrical fur- 
nace. A thoroughly practical book by the most noted amateur experi- 
menter in America. For the boy and the more mature amateur. Holi- 
days and evenings can be profitably occupied by making useful articles 
for the home or in building small engines or motors or scientific in- 
struments. Table of contents furnished on application. 
MUNN & CO. Inc., Publishers, 361 BROADWAY, NEW YORK 
CASS) CEO CSO CEFO COE SHO GSFOGSTOCSPOGLOD 
“They serve to emphasize any defects in, or 
difference in color of, concrete construction. 
“They impart to concrete a soggy, water- 
soaked appearance. 
“They do not render impermeable to mois- 
ture for any length of time. 
“They do not decorate.” 
Under his fourth heading Mr. White sum- 
marizes paints for concrete, with the practical 
conclusion that there are none which fulfil all 
the requirements of a severe list which he 
gives. ‘The principal of these are that it must 
be applicable to a wet surface and at the same 
time waterproof when set; it must be applica- 
ble to the concrete without previous treatment 
of the latter, durable, economical, and pleasing 
to the eye, must act as a bond between concrete 
and a plaster coat, and remain hard in the 
presence of water, in addition to possessing all 
the qualifications of ordinary paint such as 
working well under the brush, filling voids 
and leveling up irregularities of surface. 
Although Mr. White did not say in his 
paper that he knew of any satisfactory paint, 
we have reason to believe that he has been in- 
strumental in the production of one, or at 
least that it has been developed with a special 
view to fulfilling the requirements outlined in 
his paper. 
We have recently seen tests and the results 
of long-continued tests, of a paint called Ce- 
menthide, which seems to fulfil all the exact- 
ing conditions above referred to. 
At a cement-block factory in Newark, N. J., 
a part of the process consists of the curing of 
the newly made blocks by subjecting them to 
steam for thirty-six hours, accelerating their 
setting and providing a much more constant 
and uniform supply of moisture to the cement 
than can be obtained by spraying. 
For this purpose two curing rooms are used, 
each of which is opened to be emptied and re- 
filled on alternate days, the steam being turned 
off in the morning and on again at night. The 
steam is therefore continuously applied to the 
interior of the walls for 36 hours out of every 
48. The rooms themselves are built of con- 
crete blocks, and were formerly constantly 
saturated with moisture. It was evident from 
the outside which room was filled with steam 
from a thin film of moisture trickling down the 
exterior of the walls, which had to be drained 
away. Six months ago the interior was painted 
with two coats of Cementhide, and now there 
is no evidence of moisture on the outside of 
the walls, while the interior has a smooth, hard 
surface differing little from that of well-fin- 
ished cement except in its pleasant color. 
Blocks made identically as possible from one 
batch of concrete have been tested under vary- 
ing conditions, one plain and the other painted. 
The unpainted block was found to vary in 
weight with the water, absorbing it according 
to the amount present in the atmosphere or 
from the ground, while the weight of the 
painted block varied not at all. Blocks painted 
in a variety of pleasing colors have been left 
exposed to sun, rain, and wind for months 
without being apparently affected. Concrete 
painted with this material takes a plaster coat 
better than natural concrete, both concrete and 
plaster adhering to the paint more firmly than 
they do to each other. It has even been shown 
that the rise of moisture by capillarity in mon- 
olithic concrete set in moist ground is stopped 
by a coat of Cementhide between the top of 
the underground concrete and the masonry or 
other concrete continuation upward of the 
wall. The paint has a dull finish not unlike 
the concrete itself, but smoother and of any 
color desired, and appears to remain hard and 
to preserve the surface of the concrete indefi- 
nitely. One can not imagine a more severe test 
in any ordinary building than that imposed at 
the block factory above mentioned, and it 
would seem that this paint should have wide- 
spread possibilities when it is sufficiently in- 
troduced on the market. 
