REPORT OF NATIONAL, MUSEUM, 1925 93 



buretor, the magneto, and two of the spark plugs were specially 

 prepared by these companies for the exhibit, the spark plugs being 

 equipped with small electric lights to indicate the spark flash and 

 the magneto being so arranged that even though partially cut 

 away, it is still able to function properly. The carburetor too, has 

 been sectionalized so that the layman may see its interior construc- 

 tion. 



Henry Ford, Dearborn, Mich., presented a full-size, hand-operated 

 unit of the Ford automobile, namely, the planetary transmission. 

 The Museum purposes to visualize the several primary mechanisms 

 which compose the automobile. Besides the power plant these in- 

 clude transmissions, differentials, rear axles, and clutches, of which 

 there are several distinct types universally used. The Clark Equip- 

 ment Co., Buchanan, Mich., offered to present a full-size automobile 

 rear axle of the distinct type made by that company, but because 

 of limited exhibition space it was necessary to limit the donation 

 to an enlarged phantom photograph of the axle, which the com- 

 pany prepared especially for the Museum. 



The Portland Cement Association, Chicago, 111., through its local 

 office in Washington, D. C, presented a full-size photographic copy, 

 suitably framed, of the original patent on Portland cement granted 

 by King George IV to Joseph Aspdin in 1824. The presentation 

 was made in the presence of about a dozen officials representing 

 various departments of the Government interested in Portland ce- 

 ment. The gift was appropriately accepted on behalf of the Museum 

 by Doctor Walcott and now hangs in close proximity to the exhibit 

 of Portland cement in the Division of Mineral Technology. 



Last year the Barber Asphalt Co., Philadelphia, Pa., at consider- 

 able expense, reconditioned the model of the natural lake of asphalt 

 on the Island of Trinidad, which the company had donated to the 

 Museum about 10 years ago. This year the company devoted con- 

 siderable time and expense to revision of the exhibit of asphaltic 

 products made from natural asphalt. Four colored transparencies 

 visualizing their uses and many asphaltic products previously un- 

 represented in the Museum were added. These included types of 

 roofing papers and shingles, asphaltic paints and cements — in fact, 

 representations of practically all of the newer uses for this material. 



Part of the section of metrology of the Division of Mechanical 

 Technology is devoted to the subject of calculators and calculating 

 machines. During the year the Burroughs Adding Machine Co., 

 Detroit, Mich., presented in a speciallly designed case a series of 

 five types of calculating machines, such as are used to-day in many 

 branches of business. The series include a calculator, a billing ma- 

 chine, an automatic bookkeeping machine, an adding and listing 



