CHOOSING A LOCATION. 25 



been proved by repeated experiments to measure 

 twelve hundred and fifty gallons per minute ; as 

 each gallon will support ten pounds of trout, 

 twelve thousand five hundred pounds weight can 

 be sustained by the water of our spring. When 

 sufficient fall can be obtained, by proper aeration 

 the capacity of the water may be still greater in- 

 creased. 



Many rules, most of them involving abstruse 

 mathematical calculations, have been given for 

 ascertaining the number of gallons delivered by 

 a stream per minute. The following, however, we 

 have found to be the most simple and sufficiently 

 correct for all practical purposes. Measure the 

 width and depth of the stream where for a short 

 distance the banks are nearly parallel and the 

 depth nearly uniform ; between these parallel 

 banks throw a chip or cork into the water, and 

 note the distance it drifts during a quarter of a 

 minute ; multiply the product of the depth and 

 width of the stream by the distance traversed by 

 the chip or cork, and the product, when dimin- 

 ished by one-fifth, will give the number of cubic 

 feet delivered in a quarter of a minute. The one- 

 fifth must be deducted, as the rapidity of the 

 flow on the surface is greater than at the bottom 

 of the stream. Thus, suppose the depth of the 

 stream to be two feet and its width four, and that 



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