SECT, ix.] OF STEAM ENGINES. 277 



intendence of some respectable engineer, who should report monthly the following particulars in 

 columns : viz. 



The name of the mine ; 



the size of the working cylinder ; 



whether working single or double ; 



the load per square inch in the cylinder ; 



length of stroke in the cylinder ; 



the number of pump lifts ; 



the depth in fathoms of each lift ; 



diameter of pumps in inches ; 



time worked ; 



consumption of coals in bushels ; 



number of strokes during the time ; 



length of stroke in pump ; 



load in Ibs. ; 



Ibs. lifted one foot high by a bushel of coals ; 



number of strokes per minute ; 



and, lastly, a column for name of engineer and remarks. 



Messrs. Thomas and John Lean were appointed to the general superintendence ; and the 

 different proprietors, as well as the regular engineers of the respective mines, engaged to 

 give them every facility and assistance in their power. The first monthly report was for 

 August 1811. See Phil. Mag. vol. xlvi. p. 116. See also Appendix. 



