March 7, 1902.] 



SCIENCE. 



393 



phere passing over those lakes since the 20th 

 of December, 1901, and the warm temperature 

 has caused unusually great evaporation so that 

 the water in those lakes is only about foiir feet 

 higher at this date — February 9, 1902 — than 

 usual at this time of the year. There is also 

 but slight increase of volcanic activity, indi- 

 cated by an increased flow of gases and vapor 

 from volcanic peaks. Only seven earthquakes 

 in Western Nicaragua have occurred since 

 November 15, each slight, from II. to IV. of 

 the Eossi-Forel scale. 



There are no indications of higher water in 

 the Lakes this year. J. Crawfordes. 



Managua, Nicaragua, 

 February 9, 1902. 



UNIO CONDONI IN THE .JOHN DAY BEDS. 



Professor J. C. Merriam informs me that 

 he 'found great quantities of that species at 

 the original locality.' As this form was not 

 among the material sent to me for determina- 

 tion, I erroneously inferred that it had not 

 been detected. The original locality, as stated 

 by Dr. White, is the North Fork of John Day 

 River, Oregon, at the angle of the big bend, 

 longitude 119° 40', latitude 44° 50'. My 

 paper in Science January 24 last, pages 

 153-154, is hereby corrected in this particular. 

 EoBT. E. C. Stearns. 



NOTES ON INORGANIC CHEMISTRY. 



THE NEW SULFURIC ACID MANUFACTURE. 



Attention has often been called within the 

 last few years to the new process of making 

 sulfuric acid from the pyrites-burner gases 

 without the intervention of lead chambers, but 

 the first authoritative description of the proc- 

 ess, with the history of its development, was 

 given in a lecture last fall by Dr. E. Knietsch 

 before the German Chemical Society. This 

 lecture has now been published in the Berichte 

 of the Society and deserves notice, not only on 

 account of the intrinsic importance of the sub- 

 ject, but also as being a conspicuous example 

 of how the persistent investigations of trained 

 chemists have succeeded in overcoming what 

 seemed to be insuperable obstacles. 



The catalytic action of platinum upon mix- 

 -tures of gases was discovered by Sir Hum- 



phrey Davy in 1817, and in 1831 Peregrine 

 Phillips, of Bristol, England, took out a 

 patent for the manufacture of sulfuric acid 

 by the action of finely divided platinum upon 

 a mixture of sulfur dioxid and oxygen. This 

 process, though exploited from time to time, 

 and worked at by many chemists, came to noth- 

 ing. In 1875 Clemens Winkler took up the 

 study of this reaction, finding that the most 

 favorable condition for this reaction is when 

 the gases are present in the proportion of two 

 volumes of sulfur dioxid to one of oxygen, and 

 that the presence of other gases or even of an 

 excess of either of those involved in the re- 

 action is detrimental. Since, by decom- 

 position, ordinary sulfuric acid yields a 

 mixture of sulfur dioxid, oxygen and water, 

 it was possible to utilize these gases in the 

 manufacture of sulfur trioxid or of fuming 

 sulfuric acid, by drying them to remove the 

 water, and then leading them over platinum 

 sponge. This was put into practical applica- 

 tion with some success. This can, however, 

 hardly be considered more than a very slight 

 step toward the manufacture of ordinary oil 

 of vitriol from the pyrites-burner gases. 



The rapidly increasing development of the 

 color-industry of Germany has occasioned a 

 demand for enormous quantities of both con- 

 centrated and fuming sulfuric acid, and for 

 the past decade the energies of the chemists 

 of the great color corporations have been di- 

 rected toward the problem of the manufacture 

 of these acids without the intervention of the 

 lead chambers and the platinum concentra- 

 tion stills. In these investigations Dr. 

 Knietsch, of the Badische Anilin- und Soda- 

 Fabrik, was a most important factor, and to 

 him belongs a great share of the credit of 

 having rendered the new process a commer- 

 cial success. 



The gases from the pyrites-burners consist 

 of sulfur dioxid, nitrogen and an excess of 

 oxygen from the air. When these gases were 

 thoroughly purified and carried to the labora- 

 tory it was found that on passing over a 'con- 

 tact mass' containing finely divided platinum, 

 the sulfur dioxid was completely oxidized to 

 the trioxid, or to sulfuric acid if water was 

 present. When, however, an attempt was 



