GRIST AND SAW-MILLS. 361 



It will not be neceflliry that in any cafe the boiler flionld con- 

 tain more than 6 times as much as the receiver ; hence we have 

 for Beydier's mill with one pair of ftones, and Keyger's faw-mill 

 with 6 feet head, a receiver = 4 feet by 2.5 diameter = to 

 122.28 gallons, which multiplied by 6 = about 734 gallons for 

 the contents of the boiler. The receiver for the fame grift- 

 mill == 4 feet by 3 feet == 163 gallons, and the boiler =972 

 gallons. 



In order to prevent the water, whilfl the receiver is filling, 

 from flriking againfl: its top, it will be necefTary that one foot at 

 lead be added to its height ; fo that iuftead of being 4. feet high 

 as we have hitherto fuppofed, it fhould be atleaft 5 feet. 



3 B MEMOIR 



