32 On the Acilon of 



have been one thousard. Amongst these, I had four suc- 

 cessriil operations. I persevered, because, even in my fail- 

 ures, I saw suincicnt to convince me that I should quit the 

 road to truth if I desisted. After ail my labour and fatigue 

 I cannot sav that I had come nearer to mv object, of ob- 

 tainin'i niore certainty m my processes. Their success was 

 still aliazard on the dice, against which there were many 

 chances ; but till others had thrown as often as 1 had done, 

 they had no solid right to tieny the existence of such a com- 

 baiatiou. On ihis foundation none, 1 believe, have esta- 

 blished such a right. Messrs. Rose and Gehlen do not say 

 how often their experiments were repeated; but it is pro- 

 bable that if they had been performed very often, these au- 

 thors would not have neglected to niention it. M. Richter 

 states his merely as preparatory to more extensive researches ; 

 and M. Tromsdorti", as well as M. Klaproth, mention little 

 more than the fact. If the German chemists have con- 

 cluded against my results, they have done so witlioufjust 

 grounds, and without having bestowed upon them that 

 labour and assiduity for which they are usually so remarka- 

 ble. 



In this state of uncertainty the compound natureof palla- 

 dium received an indirect, but a very able, support from 

 some experiments of M. Ritter, the celebrated Galvanist of 

 Jena. M. Ritter had ascertaiiied the rank which a great 

 number of substances hold in a Galvanic series, arranged 

 according to the property they possess of becoming positive 

 or negative when in contact with each other. He had 

 established the following order, the preceding substance 

 being in a viiiins relation to that whi''h comes ncKt ; 

 Zinc, lead, tin, iron, bismuth, cobalt, antimony, platina, 

 gold, mercury, silver, coal, galena, crystallized tin ore, 

 kupfer nickel, sulphur pyrites, copper pyrites, arsenical 

 pyrites, graphite, crystallized oxide of manganese. He had 

 the goodness to try palladium in niy presence, and found it 

 to be removed, not only from what I believed to be its con- 

 stituent jiarts, but altogether fron) among the metals, and 

 to star.d be'iween arsenical pyriies and graphite. This re- 

 sult led M. Ritter into a new and general train of rcasonino;, 

 and induced him to undertake the examination of a great 

 number of alloys, and of a variety of amalgams. He con- 

 sidered the subieet as a philosopher, and his operations were 

 those of a consummate experimentalist. It would be doing 

 him an injustice to attempt an extract of his ingenious 

 paper, which contains a series of the most interesting ex- 

 perimmls. I shall merely observe for the present purpose, 



thiU 



