GRAVITATIONAL METHODS 383 



The carrying case is provided with shoulder straps (Figure 229). In 

 use, the meter rests on a small aluminum tripod, as shown in Figure 229a. 

 The weight of the complete equipment is approximately 15 pounds. Meters 

 of this type are extremely useful for oil reconnaissance and mining 

 surveys. 



Fig. 229. — Light weiKht poitaljlc meter for general oil recon- 

 naissance and mining surveys. (Courtesy of International Geo- 

 physics Company.) 



Electric Gauge Type Gravimeters. — Electric gauge type gravimeters 

 offer several advantages. The ratio of the displacement of the indicator 

 to the displacement under measurement can be made as high as 100,000 

 without introducing frictional effects, such as hysteresis or sticking. Also, 

 the gauge permits measurements of very high accuracy and allows remote 

 reading or recording. 



The electric gauge may utilize any one of the sensitive electric measuring 

 devices. f 



t C. M. Hathaway and E. S. Lee, "The Electric Gauge," Mechanical Engineering, Sept. 1937. 



