370 Mr. Rose's Sketch of the Geology of West Norfolk. 



This engine is at work at the Charles Town United mines 

 near St. Austell ; it was erected for us under the direction of 

 Mr. Sims, an engineer of great experience in Cornwall. It 

 differs from the general construction in being a single engine, 

 having the beam loaded at the outer end ; and the rotatory 

 motion of the crank is rendered almost completely uniform by 

 the assistance of the fly-wheels. It works nearly as expan- 

 sively as the pumping-engines. 



It was predicted, 1 understand, before the engine went to 

 work, that a steady rotative motion could not be produced in 

 this way, and some believed that the crank would never pass 

 the centre ; I can, however, bear witness that the action is ex- 

 tremely good, and will, I believe, by a little alteration in the 

 weight and diameter of the fly-wheels, be made perfect; and 

 as it must be an object to save at least one half the fuel or- 

 dinarily consumed, I point it out as deserving attention and 

 inquiry. I have desired that its performance may be regu- 

 larly reported in the monthly duty papers. 



I am informed by Captain Thomas Lean, who reports the 

 duty of most of the engines in Cornwall, that this is not the 

 first construction of the kind, but that a similar one was 

 erected formerly at Wheal Vor tin-mine by Mr. Peter God- 

 frey, and that it then surpassed in duty any other stamping 

 engine of its day, but that for some reason it never attracted 

 much notice. 



Mr. Sims is constructing a winding-engine for the same 

 mine on a similar principle. Yours very truly, 



Bedford Row, Oct. 12, 1835. John TAYLOR. 



XLVII. A Sketch of the Geology of West Norfolk. By 

 C. B. Rose, Fellow of the Royal Medical and Chirurgical 

 Society of London. 



[Continued from p. 279.] 



Chalk with Flints.— 1VTEDIAL chalk of " Geology of Nor- 



The escarpment of this bed of chalk (incumbent on the last) 

 forms the high range or downs of Norfolk, running nearly 

 due north and south from Thornham and Brancaster through 

 Docking, Great Massingham, Lexham, Litcham, Castleacre, 

 SwafFham, Hilborough, Saham-Tony, Weeting, to Thetford. 

 From this range flow the principal rivers of the county ; two 

 only, the Setchy or Nar and the Wissey or Stoke, cutting 

 through it in their western course to the sea. 



This bed is well characterized by its numerous horizontal 



