REPORT OF NATIONAL MUSEUM, 1922. 109 



to allied subjects, as well as prepared in better manner for the in- 

 struction of visitors. All other exhibits have been grouped accord- 

 ing to their motive power and chronological development. 



In aerial transportation all exhibits have been so installed as to be 

 readily studied by visitors. The development of aeronautics is fairly 

 well represented by the objects now on exhibition, and the missing- 

 steps are being filled in by models made in the division's laboratory. 

 It is planned to develop, by drawings exhibited in the swinging 

 frames, a complete history of aviation and as rapidly as possible to 

 substitute these by models. At this writing several excellent illus- 

 trations of historical aircraft pertaining to this development have 

 been exhibited. 



Firearms. — The exhibit of firearms received careful attention, as 

 well as thorough cleaning. New accessions are treated upon receipt 

 in a manner known to preserve them against rust or other injury. 

 The history of artillery is being presented by a series of four models 

 of ancient catapults, made in the division's laboratory, one of which 

 is completed and on exhibition and forms the beginning of a branch 

 of ordnance heretofore lacking in the otherwise complete collection. 



Metrology. — The horological collection has been made particu- 

 larly appealing to the public and has received constant commenda- 

 tion. Exhibits are placed in good light and in an instructive man- 

 ner, as well as being kept in excellent condition. 



As a whole, the collections in the division of mechanical technol- 

 ogy are in well-preserved condition. Some collections are handi- 

 capped for lack of space or proper cases, but, as far as possible, this 

 is being remedied. 



RESEARCHES FOR THE BENEFIT OF THE MUSEUM. 



Researches on the collections resulted in the publication during 

 the year of two papers by the curator, the first a Catalogue of the 

 Mechanical Engineering Collections of the Museum, published as 

 Museum Bulletin No. 119, and the other an article on Watchmakers 

 as Inventors, which appeared in the Keystone for June, 1922. 



In the division of mineral technology all activities are preceded 

 by special investigations relative to each particular mineral indus- 

 try in an effort to compile sufficient data on the technology and eco- 

 nomics involved in order to present it in an instructive manner to 

 the lay public. In an endeavor to bring more to completeness the 

 division's exhibits relative to the glass industry, Paul M. Frank, 

 assistant curator, spent a large part of his time in a study of the 

 plate glass, optical glass, and chemical glass phases of the industry. 

 The writer, on the other hand, devoted as much time as he could 

 find in preparing data and securing the needed cooperation for the 

 preparation of an exhibit visualizing the manufactured-gas indus- 

 try, and it is gratifying to report that the exhibit is already well 



