6 Biography of Berzelius. 
it contained in combination with silica was new. But he over- 
looked its metallic nature, and although he obtained it of a red- 
dish-yellow color, regarded it as an earth, which he called Ochroit 
earth. The investigation of Berzelius and Hisinger was evi- 
dently carried out with more precaution than that of Klaproth. 
Not only did the latter overlook the partial solubility of the oxyd 
in solutions of alkaline carbonates, he did not even remark the 
Mineralkérper,” which did not appear until 1807, that he men- 
tioned the evolution of oxy-muriatic gas on treating the ignited 
oxyd with muriatic acid, still, however, without attaching to the 
fact any great weight. Berzelius and Hisinger, on the contrary, 
justly considered this of very special importance, as unequivo- 
cally pointing out two very different stages of oxydation, at that 
time one of the principal means of distinguishing between me- 
tallic oxyds and earths, which were then regarded as simple 
bodies. Gehlen also directed attention to this point in a remark 
upon the paper of Berzelius and Hisinger. Further, he was for- 
tunate enough to accomplish, with the aid of Hjelm, the reduc- 
tion of the oxyd, and to obtain the metal in an isolated, although 
not in a melted state. 
hen Berzelius subsequently undertook the determination of 
the equivalent weights of almost all the elementary bodies by 
means of a long series of experiments, he resigned the estimation 
of the equivalent of cerium to Hisinger, and did not occupy him- 
self more specially with this metal. Thus probably the discov- 
ery of the oxyds of two other metals, accomplished by Mosander, 
thirty-six years after that of cerium, escaped him. 
Besides the examination of cerite, Berzelius undertook at that 
time the investigation of other new and interesting minerals. 
had to earn his livelihood, was that of physician. He naturally 
sought in this profession for those occupations especially in which 
was quite natural that as physician he should be induced 
to take up the study of animal chemistry. What he achieved in 
