66 REPORTS OF INVESTIGATIONS AND PROJECTS. 



registered the rainwater shall be used to complete the work of the meter, con- 

 stituting the registration of one bucketful of water. Briefly, the construction 

 and operation of the rainmeter are as follows : 



The rainwater collected by a standard funnel flows through a pipe into a 

 reservoir (R) and thence through a valve (V) into a bucket (B) suspended 

 by a chain (C) over a wheel (W). From the other end of this chain are 

 hung a variable counterweight tank (ct) which counterbalances the bucket 

 (B) and a series of weights (CW) to counterbalance the water. As the 

 bucket (B) fills, it descends, thereby lifting one by one the counterweights 

 (CW) and the counterweight tank (ct), the large dial at the same time regis- 

 tering the number of cubic inches of rainwater at any time contained in the 

 bucket (B). When it has descended sufficiently^ a lever (/) on the wheel 

 (W) will release a catch (d) and a hammer (h) will fall, closing the inlet 

 valve (V), opening an outlet syphon valve (V), and allowing the water to 

 flow into a stationary tank (T). The lessening of the weight of water in 

 the bucket (B) and the pull of the counterweights (CW) will cause the 

 bucket (B) to rise again until it is checked and held temporarily by the 

 hammer (h). This assures the complete emptying of the bucket (B) into 

 the stationary tank (T), from which the water flows into the counterweight 

 tank (ct). The additional counterweight thus created will cause the bucket 

 (B) to rise still farther, thus pushing up the hammer (h) until it is held by 

 the catch (g), closing the outlet valve (V), opening the inlet valve (V),and 

 allowing the accumulated water in the reservoir (R) to flow into the bucket 

 (B) as before. This completes the cycle of the operations necessary to the 

 registration of one bucketful (or about i8 cubic inches) of rainwater. The 

 large indicator wheel revolves and registers as the bucket (B) descends, but 

 remains stationary as the bucket (B) rises. The small indicator wheel regis- 

 ters the number of revolutions of the large wheel. 



EXPLORATIONS AND FIELD WORK. 



The experimental plantations in the Santa Catalina Mountains form a 

 series, the farthest of which is 32 miles distant from the Desert Laboratory 

 and at an elevation of a mile above it. Several visits are made to these places 

 during every season, necessitating the use of a train of pack-horses for trans- 

 porting supplies and apparatus. The region traversed is rich in material 

 of importance and the trips are timed to meet the various needs that arise. 



In the study of the origin and development of deserts and desert flora much 

 attention has been given to unmapped regions in southwestern Arizona and 

 in the desert areas in and near the delta of the Colorado River. A sailboat 

 has been constructed and designed for use on the Salton Lake, while pack- 

 trains and wagons are used elsewhere. The principal explorations of the 

 year have been made in the Pattie Basin, a depressed area forming a part of 

 the Colorado Delta in Baja California. This region is one of the most arid 



