ILLUSTRATIONS.

There is in the Survey a division organized for the purpose of preparing

illustrations for paleontologic and geologic reports. Mr. W.H. Holmes is

in charge of this division. Illustrations will not hereafter be used for

embellishment, but will be strictly confined to the illustration of the

text and the presentation of such facts as can be best exhibited by

figures and diagrams. All illustrations will, as far as possible, be

produced by relief methods, such as wood-engraving, photo-engraving, etc.

As large numbers of the reports of the Survey are published, this plan is

demanded for economic reasons; but there is another consideration believed

to be of still greater importance; illustrations made on stone cannot be

used after the first edition, as they deteriorate somewhat by time, and it

is customary to use the same lithographic stone for various purposes from

time to time. The illustrations made for the reports of the Survey, if on

relief-plates that can be cheaply electrotyped, can be used again when

needed. This is especially desirable in paleontology, where previously

published figures can be introduced for comparative purposes. There are

two methods of studying the extinct life of the globe. Fossils are indices

of geological formations, and must be grouped by formations to subserve

the purpose of geologists. Fossils also have their biologic relations, and

should be studied and arranged in biologic groups. Under the plan adopted

by the Survey, the illustrations can be used over and over again for such

purposes when needed, as reproduction can be made at the small cost of

electrotyping. These same illustrations can be used by the public at large

in scientific periodicals, text-books, etc. All the illustrations made by

the Geological Survey are held for the public to be used in this manner.

Scientific American Supplement, No. 484, April 11, 1885 · 第 40 / 55 题