ABSTRACTS: MAMMAL,OGY 343 



TECHNOLOGY. — Tests of hollow building tiles. Bernard D. Hath- 

 cocK and Edward SkiIvIvMAN. Bur. Stand. Tech. Paper No. 

 120. Pp. 29. 1919. 



These tests were made upon the types and sizes of tiles most commonly 

 used in practice, and were carried out with the idea of studying their 

 strengths and the relations existing between their various properties, 

 especially those introduced by the kinds of clays used, the method of 

 manufacture, and the positions in which they are laid. The principal 

 tests discussed are those of compression and absorption which together 

 total approximately 250. Strain readings were taken upon some with 

 an 8-inch Berry strain gage for moduli determinations. The testing 

 machines used were of the Olsen Universal type. 



The results obtained show the loads at incipient failures, the maxi- 

 mum compressive strengths, and the moduli of elasticity of the various 

 types and size of the tiles tested on end, on edge, and flat. Relation- 

 ships are established between the moduli of elasticity and the com- 

 pressive strengths, the colors of the tiles Ind their compressive strengths, 

 the colors of the tiles and their moduli of elasticity, the percentages 

 of absorption and the compressive strengths, and the percentages of 

 absorption and the colors of the tiles. B. D. H. 



MAMMALOGY. — East African mammals in the United States Na- 

 tional Museum. Part 2. Rodentia, Lagomorpha, and Tubuli- 

 dentata. N. Holuster. U. S. Nat. Mus. Bull. 99, part 2. 

 Pp. i-x, 1-184, pis. 1-44, fig. I. May 16, 1919. 

 This second volume of a report on the mammals from Eastern Equa- 

 torial Africa contained in the collections of the National Museum 

 lists 4,863 specimens of rodents, hares, and aardvarks, all but 100 of 

 which were collected by the Smithsonian African Expedition, under the 

 direction of the late Col. Theodore Roosevelt, 1909-10, and by the Paul 

 J. Rainey African Expedition, 1911-12. The richness of the National 

 Museum collection of East African mammals is well illustrated by the 

 fact that in the two parts of this work so far published, dealing only 

 with six orders of mammals, are listed 6,696 specimens, including 142 

 types; representing 349 valid species and subspecies. The plan of 

 arrangement of the text adopted in the first volume has been followed 

 throughout, and the geographical limits are the same. A list of all 

 localities with index references to an accompanying map; generic and 

 specific synonymies; type localities and location of type specimens; 

 critical notes on distribution, habits, nomenclature, and taxonomy; 

 lists of stations where each form was collected; and full tables of 

 measurements of specimens are included. The skulls of all type speci- 

 mens are figured natural size. It is hoped that a third volume, contain- 



