266 Mr. Farcy's Statement of Geological Facts 



of the pan ; and upon this circumstance depends the whole 

 secret t^f getting qait ot the steam. If you remove these 

 boards or partial coverings, the steam chimney loses all its 

 use. The letter b shows the part of the top of the pan 

 which sh<inld be left open to admit to the workmen a ready 

 communication with the hot water, and through this open 

 part a current of cold air is constantly seen to press and 

 force the steam rapidly up the steam chimney. 



It is proper to add, ihat there must always be an empty 

 ' space of two or three inches between the surface of the hot 

 water and the under part of the cover cc, so as to permit the 

 steam to pass to the bottom of the steam chiinney. To 

 effect this purpose, and at the same time to allow the cop- 

 per to be full of hot water, a rim or curb of wood F, about 

 three inches thick, should be fixed upon the top of the 

 copper, and upon this the covering boards cc placed; this 

 allows sufficient room for the steam to press forward to the 

 steam chimney at all times. 



The cover and wooden steam chimney are removeable, 

 and may serve for another copper if both are not wanted at 

 the same time. 



XL, Geological Observations on the County of Antrim , and 

 others in the North-east Pari of Ireland, in an Attempt 

 to arrange the rnimerous Facts, stated by Dr. William 

 Richardson to the Royal Irish Academy, and to the 

 Royal Society*, and those recently published in the Rev. 

 John Dobourdiru's Statistical Survei/ of Antrim, by 

 Dr. William H. Drummond, in the Preface and Notes 

 to his Poem " The Giant's Causeivay," &c. and to refer 

 each of them to one of four principal Strata ; separating 

 such as belong to the Alluvia : with incidental Facts and 

 Observations respecting other Districts, &c. &c. By Mr. 

 John Farev Senior, Mineral Surveyor. 



To Mr, Tilloch. 



Sir, -I- HE announcement which Dr. William Richardson 

 made in y? ,ir 37th volume,' page 368, of the Rev. John 

 Dubourdieu being employed on a Statistical Survey of the 

 County of Antrim in Ireland, to which he meant to con- 

 tribute his assistance, as to the Geological Facts of that 

 most interesting County, has made me anxiously expect the 

 appearance of ihis^volume : and in the perusal of which I 



* See vols, xxxv, and xxxiii of this Magazine, 



have 



