134 



49. Fo/ these tests, pats about 7% cm. (2.95 in.) in 

 diameter, 1% cm. (0.49 in.) thick at the center, and taper- 

 ing to a thin edge, should be made, upon a clean glass 

 plate [about 10 cm. (3.94 in.) square], from cement paste 

 of normal consistency. 



60. Normal Test: A pat is immersed in water main- 

 tained as near 21 C. (70 F.)) as possible for 28 days, 

 and observed at intervals. A similar pat is maintained in 

 air at ordinary temperature and observed at intervals. 



51. Accelerated Test: A pat is exposed in any con- 

 venient way in an atmosphere of steam, above boiling 

 water, in a loosely closed vessel. 



52. To pass these tests satisfactorily, the pats should 

 remain firm and hard, and show no signs of cracking, dis- 

 tortion or disintegration. 



53. Should the pat leave the plate, distortion may be 

 detected best with a straight-edge applied to the surface 

 which was in contact with the plate. 



RECENT TESTS ON BEAMS. 



In order to enable the readers of this book to form their 

 own conclusions relative to the various tests which have 

 been made within the last few years we publish the 

 tables compiled by Profs. Hatt, Talbot, Turneaure, Mar- 

 burg, Lanza, Howe and Mr. Harding, also those tests on 

 columns made at the Watertown Arsenal. For a com- 

 plete discussion of the same the reader is referred to 

 Reinforced Concrete by Charles F. Marsh. Also Buel & 

 Hill. These tables appear on pages 136 to 151 inclusive. 



TABLE OF LINEAR MEASURES. 

 (M. M.) (C. M.) 



10 millimeters =1 centimeter 0.3937 in. 



10 centimeters =:! decimeter 3.937 in. 



10 decimeters r=l meter .r: 39.37 in. 



10 meters =1 dekameter =393.37 in. 



10 dekameters =1 hectometer rz 328.00 ft. 1 in. 



10 hectometers x=l kilometer = 0.62137 miles. 



(k. m.) 

 10 kilometers = 1 myriameter - 6.2137 miles. 



The meter is used in general, the centimeter or milli- 

 meter in reckoning short distances, and the kilometer 

 for long distances. 



A centimeter is about % of an inch. 



A meter is about 3 ft. 3% in. 



A kilometer is about 200 rods, or % of a mile. 



