509] Museum-History and Museums of History. 265 
The museum must, in order to perform its proper func- 
tions, contribute to the advancement of learning, through 
the increase as well as through the diffusion of knowledge. 
We speak of “ educational ” museums and of the “ educa- 
tional method of installation so frequently that there may 
be danger of inconsistency in the use of the term. An edu- 
cational museum, as it is usually spoken of, is one in which 
an attempt is made to teach the unprofessional visitor of 
an institution for popular education, by means of labelled 
collections, and it may be, also, by popular lectures. A 
college museum, although used as an aid to advanced in- 
struction, is not an “ educational museum ” in the ordinary 
sense, nor does a museum of research, like the Museum of 
Comparative Zoology at Cambridge, Massachusetts, belong 
to this class, although, to a limited extent, it attempts and 
performs popular educational work in addition to its other 
functions. 
In the National Museum in Washington the collections 
are divided into two great classes : the exhibition series, 
which constitutes the educational portion of the museum, 
and is exposed to public view, with all possible accessories 
for public entertainment and instruction ; and the study 
series, which is kept in the scientific laboratories, and is 
rarely examined except by professional investigators. 
In every properly conducted museum the collections 
must, from the very beginning, divide themselves into these 
two classes, and in planning for its administration, provi- 
sion should be made, not only for the exhibition of objects 
in glass cases, but for the preservation of large collections 
not available for exhibition, to be used for the studies of a 
very limited number of specialists. Lord Bacon, who, as 
we have noticed, was the first to whom occurred the idea 
of a great museum of science and art, complains tjins, 
centuries ago, in his book “ On the Advancement of Learn- 
ing,” that up to that time the means for intellectual prog- 
ress had been used exclusively for “ amusement ” and 
“ teaching,” and not for the “ augmentation of science.” 
The boundary line between the library and the museum 
is neither straight nor plain. The former, if its scope be 
