AEROGRAPHER'S MATE 3 & 2 



funnel, which fit over the top of a tripod- 

 moanted overflow container, and a clear plas- 

 tic measuring tube. The rainfall drains from 

 the collector ring through the funnel into the 

 measuring tube, which has graduations in the 

 wall for •direct reading to the nearest hundredth 

 of an inch. (See fig. 4-16.) 



The procedures for taking the measurements 

 were discussed earlier in the chapter. 



The only maintenance required for the stand- 

 ard 4-inch rain gage is to keep it clean at all 

 times and make sure it is mounted firmly. 



TIPPING BUCKET RAIN GAGE 



The tipping bucket rain gage ML-558 (fig. 

 4-17) was originally designed for use with the 

 AN/GMQ-14( ) Semiautomatic Meteorological 

 Station but has been adapted for use with the 

 AN/GMQ-23( ) Automatic Weather Station. 



Operation 



A tipping bucket rain gage is mounted in 

 a housing which permits rain to fall directly 

 on the gage. The tipping bucket is a two-com- 

 partment container (fig. 4-18) which pivots within 



209.91 

 Figure 4-16. — Standard 4-inch rain gage (ML- 

 217). 



209.400 

 Figure 4-17. — Tipping bucket rain gage ML-558. 



a casting. Rainfall enters through the upper 

 funnel in the housing into one compartment 

 of the bucket until 0.01 inch of rainfall has 

 accumulated. The weight of this amount of rain 

 unbalances the bucket, causing the unit to tip 

 on its pivots, dumping the accumulated rain- 

 water, and moving the other compartment di- 

 rectly under the funnel. 



When the bucket tips, its rainfall content 

 falls into a funnel beneath the bucket. At the 

 base of the funnel is a drain cock, which in 

 its closed position permits the rain to collect 

 so that it may be drained into the cylinder 

 below the funnel at the time of measurement. 

 If no purpose in measuring the rainfall at a 

 given time exists, the drain cock may be left 

 open and the cylinder removed. 



The tipping motion of the bucket actuates 

 a mercury switch in the casting. Momentary 



63 



