128 REPORT OF NATIONAL. MUSEUM, 1924 



the polygonal construction been completed, would have formed the 

 fifteenth section. Each section is accordingly a truncated wedge- 

 shape and the interior exhibition surfaces are considerably smaller 

 than the exterior. In the case of both these types of cases the space 

 for the exhibition of the specimens is furnished by two diaphragms, 

 one extending out from the back of the case with a slight downward 

 slope, and the other extending up and back in the same manner until 

 terminated by the top of the case. Both of these surfaces are fitted 

 with narrow strips of molding for the purpose of supporting the 

 coins arranged at intervals of about two and one-half inches. The 

 diaphragms bearing these moldings were originally painted a dull 

 black, but after careful consideration it was decided to change this 

 to a light gray for the purpose of securing better lighting facilities 

 for the specimens and eliminating, as far as possible, the reflections in 

 the glasses, which were originally of unusual proportions. In addi- 

 tion to this improvement of vital importance in connection with the 

 exhibition of numismatic specimens, a series of special electric light- 

 ing fixtures were placed above each unit with specially frosted 

 globes which afford a maximum of lighting with a minimum of 

 reflection. In the interest of the securit}^ of the many valuable 

 specimens, new and substantial locks were installed at each end of 

 every section. This effected a very great improvement over the 

 single original central lock formerly employed for this purpose. 

 By these various processes the cases were rendered as suitable as 

 possible for the installation of the valuable specimens they were de- 

 signed to accommodate. 



The mechanical difficulties in this connection having been solved 

 in the manner stated, the actual installation of the coins was begun. 

 It was very essential therefore to adopt a better method of ar- 

 rangement which would assure to the vistior a clear understanding 

 of the general scheme and at the same time fulfill the scientific re- 

 quirements connected with the installation of such a large general 

 collection. It was also essential to adopt an arrangement which 

 would allow the collection to be expanded and new issues of coins 

 to be added with as little disturbance of the original arrangement 

 and general scheme as possible. In order to accomplish these aims 

 a larger exhibition space was required than that originally devoted 

 to the collection as originally installed in the Philadelphia Mint. 

 Consequently, although the exhibition cases derived from that source 

 are completely filled, there is not at present available the space neces- 

 sary for the oriental coins which form a very important part of the 

 collection. Plans have accordingly been made for the installation 

 of these coins in a series of additions to the present cases which 

 are to be constructed during the coming fiscal year. The coins 

 which have already been installed are divided into five main groups. 



