86 



FERGUSON'S LECTURES. 



LECT. 7th column, that the number of cogs in the^ wheel, and 

 ^^ staves in the trundle, are so near the truth for the re- 

 quired purpose, that the least number of revolutions of 

 the millstone in a minute is between 59 and 60, and the 

 greatest number never amounts to 61. 



The MILL-WRIGHT'S TABLE. 



Such a mill as this, with a fall of water about 7 feet 



