ANNIVERSARY ADDRESS OF THE PRESIDENT. XXXIX 



Percival Norton Johnson, E.E.S., assayer, metallurgist, and 

 refiner, of Hatton Garden, died June 1st, 1866, aged 73. He 

 was the eldest son of John Johnson, at one time the only com- 

 mercial assayer in London ; and after working with his father for 

 some years, he established himself in Hatton Garden half a 

 century ago. 



He rapidly rose to the highest eminence as an assayer and metal- 

 lurgist, and his opinion was so much sought after that he could 

 hardly get through the work which crowded upon him. 



The extreme accuracy of his assays (viz. in reporting the actual 

 contents of gold and silver, which before had only been done 

 approximately) soon caused them to be called in question, and to be 

 refused by the buyers of bullion, the advantage in buying upon 

 them being less than upon the ordinary assays. Upon this being 

 represented to him by the merchants, he at once stated that he was 

 willing, if required, to purchase all bars upon his own assays. And 

 this was the origin of his taking up the refining-business, thus, as it 

 were, compulsorily thrown upon him. In this he was so success- 

 ful that it has ever since continued to be a veiy important branch 

 of the Hatton Garden business, and the largest of its kind in the 

 world. His ability in this (as in all other branches that he entered 

 upon) was soon recognized publicly; and when the gold bars from 

 the Brazilian " Gongo Soco" mines, which came over in very large 

 quantities, were refused at the Mint on account of brittleness, he 

 was consulted on the matter, and undertook to refine and toughen 

 them, in which he perfectly succeeded, and the whole of the Bra- 

 zilian gold was from that time worked at Hatton Garden. 



It was in this gold that he discovered the existence of Palladium ; 

 and having succeeded in its separation, he introduced it commer- 

 cially, at once determining and making known the best uses to 

 which it could be applied. At one time he was able to supply this 

 metal at 14s. per oz. ; it is now so scarce that it sometimes realizes 

 ten guineas per ounce. 



When the Geological Society determined, in 1846, to employ this 

 interesting and rare metal for the Wollaston medal, they applied to 

 Mr. Johnson to supply it, and he generously responded by making 

 it a pleasure, for many years, to present it gratuitously to the 

 Society. 



After he had been in business some years, he visited Germany, 

 and was much interested in the mining-operations of certain dis- 

 tricts there, to which he gave special attention. It was at this 

 time that he met with the compound alloy called " German silver," 

 then in a very crude and imperfect state of manufacture. He 

 brought over with him some of the substance, analyzed it, and upon 

 the basis of his analysis commenced its manufacture, with much 

 profit to himself. He was the first person in England who actually 

 made it ; and he carried on its manufacture and introduced it to gene- 

 ral use, laying the foundation of the enormous business which has 

 since arisen in this branch of metallurgy. 



At that tiaae the rough Pottery Nickel was merely ground and 



