XII AMERICAN HOMES AND GARDENS February, 1911 
WOLFF PLUMBING GOODS 
FIFTY -SIX YEARS OF QUALITY 
The renting agent calls atten- 
tion to the WOLFF PLUMBING 
FIXTURES as his best guarantee to 
the prospective tenant of the high 
grade of the plumbing system—in- 
deed, the type of the whole build- 
ings is many times inferred from 
the use of WOLFF material 
throughout. When renters be- 
come builders, the worries from 
‘‘assembled’’ plumbing,  con- 
trasted with the perfect service 
of the all- built - by - one- house 
WOLFF plumbing, makes it easy 
for the architect to use WOLFF 
specifications. 
9 ESTABLISHED 1855 
L. Wolff Manu- 
facturing Co. 
MANUFACTURERS OF 
Plumbing Goods Exclusively 
The Only Complete Line Made By Any One Firm 
GENERAL OFFICES: 
601 to 627 W. Lake St., Chicago 
DENVER TRENTON 
Showrooms: 91 Dearborn Street, Chicago 
BRANCH OFFICES: 
ST. LOUIS, Mo., 2210-2212 PINE STREET SAN FRANCISCO, CaL., MONADNOCK BUILDING 
MINNEAPOLIS, MINN., 615 NORTHWESTERN BUILDING OMAHA, NEB., 1116-1118 DOUGLAS STREET 
CLEVELAND, On10, BUILDERS EXCHANGE WASHINGTON, D.C., 327 BOND BUILDING 
KANSAS CITY, Mo., 1204 SCARRETT BUILDING BUFFAI.O, N. Y., 61 MANCHE*TER PLACE 
CINCINNATI, On10, 506 Lyric BUILDING 
JUST PUBLISHED 
Popular Handbook for Cement and Goncrete Users 
By MYRON H. LEWIS, C. E. 
Octavo (6% x 9% inches) 500 Pages, 200 Illustrations. 
AC Price, $2.50, Postpaid 
CEMEN 
Te USERS). HIS is a concise treatise on the principles and methods employed in 
the manufacture and use of concrete in all classes of modern work. 
The author has brought together in this work, all the salient matter of 
interest to the users of concrete and its many diversified products. The 
matter is presented in logical and systematic order, clearly written, fully 
illustrated and free from involved mathematics. E-verything of value to the 
concrete user is given. It is a standard work of reference covering the 
various uses of concrete, both plain and reinforced. Following is a list of 
the chapters, which will give an idea of the scope of the book and its 
thorough treatment of the subject: 
Hydraulic. V. Lime Plasters. VI. Natural Cements. VII. Portland Cement. VIII. Inspection and 
Testing. IX. Adulteration; or Foreign Substances in Cement. X. Sand, Gravel, and Broken Stone. 
XI. Mortar. XII. Grout. XIII. Concrete (Plain). XIV. Concrete (Reinforced). XV. Methods and 
Kinds of Reinforcements. XVI. Forms for Plain and Reinforced Concrete. XVII. Concrete Blocks. 
XVIII. Artificial Stone. XIX. Concrete Tiles. XX. Concrete Pipes and Conduits. _XXI. Concrete 
Piles. XXII. Concrete Buildings. XXIII. Concrete in Water Works. XXIV. Concrete in Sewer Works. 
XXV. Concrete in Highway Construction. XXVI. Concrete Retaining Walls. XXVII. Concrete Arches 
and Abutments. XXVIII. Concrete in Subway and Tunnels. XXIX. Concrete in Bridge Work. 
XXX. Concrete in Docks and Wharves. XXXI. Concrete Construction Under Water. XXXII. Con- 
crete on the Farm. XXXIII. Concrete Chimneys. XXXIV. Concrete for Ornamentation. XXXV. Con- 
crete. Mausoleums and Miscellaneous Uses. XXXVI. Inspection for Concrete Work. XXXVII. Water- 
proofing Concrete Work. XXXVIII. Coloring and_Painting Concrete Work. XXXIX. Method for 
Finishing Concrete Surfaces. XL. Specifications and Estimates for Concrete Work. 
MUNN & CO., Inc., Publishers 361 Broadway, New York 
A NEW VIEW OF THE MIGRATION 
OF BIRDS 
HE still unsolved problem of the mi- 
gration of birds has recently given 
further incentive to interesting inves- 
tigation. The most salient feature of the 
latter is the origin of the paths of passage. 
To the directions of migration which birds 
of passage take when going to and from 
their winter quarters they hold with 
most obstinate faithfulness, even when 
such directions describe greatly circuit- 
ous routes, making every effort to reach 
very far abodes for the winter, though 
equally favorable places may be found 
much nearer to their brooding regions. 
So it happens that delicate singers, and 
weak flyers like the quail, do not shrink 
from flight over great stretches of sea, 
and that summer-birds of the high north 
wander regularly every year in the fall 
to the extreme south, to the Cape and to 
Australia. Precise proof of the tenacity 
with which many birds cling to their old 
paths of migration is afforded by the 
conduct of the white wagtail, for in- 
stance. While in winter it passes to the 
very interior of Africa, it may be found 
in summer anywhere in Europe and 
Asia, even in Greenland. From the latter 
country it never wanders in winter into 
North America, which, of course, can be 
reached with greater ease, but always 
follows the old road over which it first 
must have reached Greenland, that is, by 
way of Iceland, the Faroe Islands and 
England, which were once connected 
with one another by bridges of land as 
were still at the time of the Deluge, the 
three peninsulas of Southern Europe 
with Africa. In these habits may be ob- 
served phenomena of heredity in defer- 
ence to which, during the winter, every 
individual seeks, if not the locality which 
was the site of its origin, at least the 
regions that border the line of migration 
along which its progenitors either ex- 
panded their sites of residence’ or 
founded new homes. As migratory birds 
usually, from preference, pass from one 
station of rest to another and therefore 
must follow, in a measure, the outlines 
of the country, it may be assumed that 
when they wander across the ocean, 
though elsewhere paths of migration 
overland are at their disposal, they fol- 
low in accordance with old habit lines of 
coast which disappeared long ago. 
In this way may be explained the fact 
that the hawk that broods in Eastern 
Siberia and Manchuria passes the winter 
in India and South Africa. Likewise 
wander the hoopoe and the crookbilled 
strand-snipe to Madagascar, while both 
are unknown in Africa south of the 
Equator. They follow the long chain of 
islands along which the migration of 
their ancestors toward the southwest 
occurred, and we can assume nothing 
other than that this migration was 
effected along a northern territorial con- 
nection, it may be by way of Syria and 
Arabia, along the eastern coast of the 
black continent, or perhaps along the 
chain of islands, which, as relics of a 
former continent, might have been pres- 
ent in far greater number in the past 
than at the present day. It is, therefore, 
a valid conclusion that in the course of 
time the flight overland, over a path of 
bridges of land, has become a migration 
across the ocean. The birds, however, 
did not choose the bridges of land espe- 
cially to avoid passage across the sea and 
ocean; rather their path of migration was 
the result of the fact that the former ter- 
inte 
