118 Mr. Keating on Cadmia found in Iron-furnaces. 



Having been informed that ore from the same bed was used 

 nt the works belonging to Messrs. Holley and Coffing, near 

 Sahsbury, I repaired there with a hope of finding the cadmia 

 near that furnace also. After a short search, I found it in its 

 immediate vicinity, and was informed by Mr. Holley, that he 

 had himself taken it out of his furnace about twelve years ago, 

 when they renewed the stack. He was positive that it was 

 the same ; that it had been found about six feet below the ori- 

 fice of the furnace, and that if not occasionally removed, it 

 would have eventually choked it. I even understood him or 

 his partner to say, that this substance was even at present oc- 

 casionally formed in the furnace in pieces of almost one-eighth 

 of an inch in thickness. One of the reasons why it is still 

 formed at Salisbury, and not at Ancram, is probably owing to 

 the ore used at Ancram being picked, and the other not. 

 Mr. Patterson thinks his ore is also better roasted. 



According to Mr. Heron de Villefosse, a similar substance 

 is formed in the copper and lead furnaces of Julius, Sophia, 

 and Ocker, near Goslar, in the Hartz. At Goslar, as well as 

 at Jemmapes in Belgium, this cadmia is considered as the best 

 material that could be used in the manufactui'e of brass ; as it 

 is purer than the roasted calamine, it is preferred to it, as well 

 as to all other zinciferous substances. It liad not, I believe, 

 been used in Belgium before Mr. Bouesnel described it. 

 Should it be found in any quantity at our furnaces, it would 

 no doubt be equally advantageous to work it with copper for 

 brass. 



This substance has not yet been observed in many places. 

 1 believe the only spot where it has been noticed, in addition 

 to the above mentioned, is at Verrieres, in France, where I 

 discovered it in the year 1819*. I am inclined to think that 

 if more care were taken by our iron-masters in observing the 

 progress of their furnaces, and the products which they yield, 



* As no account of the cadmia of Verrieres has as yet been published, 

 I shall here add the note which I made on the subject in my journal. 

 " July G, 1819. 1 visited the furnace of Verrieres, in the department de 

 la Viennc, in France. The director mentioned that his ore was good, and 

 that the iron it produced was likewise good. He complained, however, of 

 a substance which formed in the furnace, five feet below its orifice ; it was 

 in the form of a ring. It would, he said, have choked the furnace if not 

 removed, which at times was a difficult undertaking. I mentioned to him 

 that it appeared to be analogous to the cadmia of Belgium. The speci- 

 mens which I took with me were heavy, compact, and of a dark colour." 

 — -I have not had an opportunity of analysing them since ; but my suspi- 

 cions on this subject were conP.rmed, when, on returning to Paris in the 

 autumn of 1820, I was informed that the engineer of mines DeCressac liail 

 discovered calamine in that vicinity the year before. 



