296 A CENTUEY OF SCIENCE 



probably fair to say that Penfield did the most accurate 

 work in mineral analysis that has ever been accom- 

 plished, and that he was similarly successful in crystal- 

 lography and other physical branches of mineralogy. 



The American analytical investigations that have been 

 mentioned were all published in the Journal, with the 

 exception of a part of Gibbs's work. Many other Amer- 

 ican workers at mineral analysis might be alluded to 

 here, but only the excellent work of a number of chemists 

 in the United States Geological Survey will be mentioned. 

 Among these Hillebrand deserves particular praise for 

 the extent of his investigations and for his careful 

 researches in improving the methods of rock analysis. 



To our own Professor Gooch especial praise must be 

 accorded for the very large number of analytical methods 

 that have been devised, or critically studied, by him and 

 his students, and for the excellent quality of this work. 

 The publications in the Journal from his laboratory 

 began in 1890 (39, 188), and the extraordinary extent of 

 this work is shown by the fact that the three hundredth 

 paper from the Kent Laboratory appeared in May, 1918. 

 These very numerous and important investigations have 

 been of great scientific and practical value, and they have 

 formed a striking feature of the Journal for nearly 30 

 years. In 1912 Gooch published his "Methods in Chem- 

 ical Analysis, " a book of over 500 pages, in which the 

 work in the Kent Chemical Laboratory up to that time 

 was concisely presented. Among the many workers who 

 have assisted in these investigations, P. E. Browning, W. 

 A. Drushel, F. S. Havens, D. A. Kreider, C. A. Peters, L 

 K. Phelps and E. G. Van Name are particularly promi- 

 nent. Besides many other useful pieces of apparatus, 

 the perforated filtering crucible was devised by Gooch, 

 and this has brought his name into everyday use in all 

 chemical laboratories. 



Volumetric analysis was originated by Gay-Lussac, 

 who described a method for chlorimetry in 1824, for 

 alkalimetry in 1828, and for the determination of silver 

 and chlorides in 1832. Margueritte devised titrations 

 with potassium permanganate in 1846, while Bunsen, not 

 far from the same time, introduced the use of iodine and 

 sulphur dioxide solutions for the purpose of determining 



