THE TOI 
The United States Geological Survey is making a standard 
pographic atlas of the United States. This work has been in 
]ogress since 1882, and its results consist of published maps of 
ore than 40 per cent of the country, exclusive of outlying 
^sessions. 
iThis topographic atlas is published in the form of maps or 
las sheets measuring about 16f by 20 inches. Under the 
neral plan adopted the country ls divided into quadrangles 
funded by parallels of latitude and meridians of longitude. 
<iese quadrangles are mapped on different scales, the scale 
iected for any quadrangle depending on its nature and its 
obable future development, and consequently though the : 
mdard atlas sheets are of nearly uniform size they represent 
eas of different sizes. On the lower margin of each sheet are 
inted graphic scales showing distances in feet, meters, and 
lies. In addition, the scale of the map is shown by a repre- 
ntative fraction expressing a fixed ratio between linear 
easurements on the map and corresponding distances on the 
bund. For example, the scale 
62.500 
means that l unit on 
e map (such as 1 inch, 1 foot, or 1 meter) represents 62,500 
hilar units on the earth’s surface. i 
The standard scales used on these maps are multiples of 
e fraction Quadrangles in thickly settled or indus- 
or 
ally important regions are mapped on a scale of 
out 1 mile to an inch, and cover areas measuring 15 in 
