xxviii OBITUARY NOTICES OF MEMBERS DECEASED. 



work on the cobalt bases and another greater work yet to be men- 

 tioned, he should publish many papers of less extent. From the 

 hand of such a master, these papers are valuable and important. 

 ]\Iany relate to analytical methods ; many relate to the analytical 

 methods of the platinum metals, or to new compounds of the 

 platinum metals. These papers are numerous ; most of them are 

 too technical for presentation here, but one of them is especially 

 worthy to be mentioned and to be mentioned in this city. The 

 electrolytic determination of copper was first published from the 

 laboratory of the Lawrence Scientific School and the whole field of 

 electro-chemical analysis, nowhere cultivated more successfully than 

 in Philadelphia, was opened by Gibbs. In collaboration with E. R. 

 Taylor, he devised filters composed of insoluble powders like glass 

 and sand ; then Munroe, another student, invented porous porcelain 

 cones for filtration, and Gooch, an assistant of Gibbs, invented 

 perforated crucibles with filters composed of layers of asbestos fibre 

 made into a felt, in place of which we now often use spongy 

 platinum. So the use of filters which do not change weight on igni- 

 tion and which do not require us to heat reducible substances in 

 contact with carbon, is due to Gibbs. 



The most remarkable work of Gibbs is contained in his series of 

 researches on the complex inorganic acids, whose publication began 

 in 1877 and was continued till after 1890. Some complex inorganic 

 acids were already well known ; for instance, phosphomolybdates 

 are in common use. But, in his first paper, Gibbs showed that, 

 far from being exceptional compounds, they were members of an ex- 

 tensive class ; that the formation of complex acids was characteristic 

 of tungstates and molybdates to an extraordinary degree ; and that 

 the possible number of such compounds was vast. After this pre- 

 liminary announcement, Gibbs determined the true composition 

 of the sodium tungstates. Then he prepared phosphotungstates 

 and phosphomolybdates, and similar compounds with arsenic in 

 place of phosphorus. From this beginning, the work developed in 

 directions which cannot be well described except to an audience 

 of chemists; taking in all the degrees of oxidation of phosphorus, 

 with all the known variations in the amount of replaceable hydrogen 



