EVOLUTION OF SCIENTIFIC SERIALS. 
239 
is opposed measurably by the bibliographer and librarian 
and decidedly by the publisher, its force is such that it has 
found expression in the publications of almost all the scien¬ 
tific societies. More than half of the changes in form and 
plan of serials have been made in obedience to the need 
of prompt issue; and while promptness is opposed by in¬ 
ertia and tends to degrade into sluggishness, the mean 
interval between regular issues has materially diminished 
in nearly all of the societies, and is less in the younger than 
it was in the older at corresponding stages. 
The author needs large plates for the illustration of certain 
subjects; and with this actual need goes the fanciful require¬ 
ment which leads to publication in sumptuous form. But 
the need for large plates has diminished with the improve¬ 
ment and reduction in cost of illustrations; wood-cuts in 
the text are now used where steel or copper-plate engraving 
was formerly necessary; photo-engravings replace elaborate 
lithographs; and the art of lithography has been so im¬ 
proved that maps, diagrams, etc., maybe published upon 
smaller scales than formerly. At the same time students 
have found 4to volumes unwieldly, librarians have found 
them a source of inconvenience in their libraries, authors 
have found their issue dilatory and their circulation limited, 
and publishers have found them expensive. All of these 
objections to the 4to have had influence, and publication in 
that form has declined notably, despite the definite plans and 
sustained efforts of most of the scientific societies. 
Publication in large units or fractions involves the accu¬ 
mulation of a considerable volume of matter in the hands of 
the publisher before the first pages are printed, and this oc¬ 
casions delay; but such delay is inconsistent with the satis¬ 
faction of the common need of student and author for prompt 
issue. So this paramount requirement finds expression also 
in the small and frequent issues to which nearly all the so¬ 
cieties have been forced. 
Publishers of regular periodicals of uniform size find it 
necessary to keep on hand a large amount of copy, upon 
