TIN-PLATES 



1015 



of an inch thick ; these were 

 re-heated, cut up, and after- 

 wards passed through rolls, 

 reducing them to ' bars,' 6 

 inches by half an inch. These 

 were known in the trade as 

 ' hollow fire iron,' or ' tin- 

 bars.' The result of Mr. 

 "Watkin George's improve- 

 ments was, to reduce the 

 cost and double the produc- 

 tion with the same outlay 

 in machinery. All the tin- 

 plates made at this time had 

 the great defect of a roxigh 

 and smooth side. In the 

 year 1820, Mr. Wm. Daniell 

 found a mode to remedy this 

 defect. Himself a maker of 

 tin-bars and plates, he had 

 observed that the smooth side 

 of the plate was always that 

 corresponding to the flat part 

 of the ' portal,' or ' staff; ' he 

 at once, having ascertained 

 this cause, remedied the de- 

 fect by hammering out the 

 pile, notching it, and doubling 

 it over, so that the tilted 

 blade of the ' staff' was on 

 the top as well as the bottom 

 of the pile. This was tho 

 invention of 'tops and bot- 

 toms,' and the writer need Ljvjito 

 not remind practical men of 

 the immense sums made by 

 this discovery during the past 

 fifty years. 



Another improvement since 

 1807, is the use of the run- 

 ning-out fire ; it is still adopt- 

 ed in only a few works. 

 This is represented by figs. 

 2004, 2005, and 2006. Fig. 

 2004 is a vertical section ; 

 fig. 2005 a horizontal sec- 

 tion ; and.%. 2006 a front ele- 

 vation. This process saves 

 waste of heat and labour, by 

 running the refined metal 

 at once into the charcoal- 

 finery. 



The ' tin-bars ' before re- 

 ferred to, 6 inches by half 

 an inch, are heated and run 

 through rollers until they 

 form a sheet of sufficient 

 width ; this sheet is then 

 doubled and passed through 

 the rolls, and this repeated 

 until this sheet is quad- 

 rupled, the laminae are then 

 cut to size, and separated as 

 before described. The writer 

 asks careful attention to the 

 fact, that the last part of the 

 rolling is done when the iron 



2004 



