158 Scientific Intelligence. 



The chief scientific result from the study of the earthquake, as 

 has indeed been already discussed in this Journal (vol. xxxv, 1, 

 188S), is the conclusion as to the speed of propagation of the 

 earthquake-wave, the result being 3'226±0 , 14'7 miles, or 5192db 

 236 meters per second. This velocity is not only entitled to much 

 greater weight than results obtained in connection with similar 

 phenomena elsewhere, but, further, it agrees closely with the cal- 

 culated rate of propagation of a wave in an elastic, nearly homo- 

 geneous, solid medium of materials corresponding to those here 

 involved. Capt. Dutton's chapter upon the nature and mechan- 

 ism of wave motion is an excellent summary of the subject. As 

 exhibited on plate xxvi, there were found to be two epicentral re- 

 gions near Charleston, one 15 miles northwest near Woodstock, 

 about which the isoseismals are nearly circular ; the other to the 

 south of this and 12 miles west of Charleston, on Rantowles 

 Creek, with oval isoseismals, the major axis extending toward 

 Woodstock. At the former center, the deduced depth of the 

 focus is 12 miles, with a probable error of 2 miles; at the other 

 the material for conclusion was less satisfactory, but the depth is 

 made about 8 miles. Plate xxix gives the isoseismals over the 

 whole country, extending from the Atlantic border to a little 

 west of the Mississippi and north through the center of the Great 

 Lakes. No definite conclusion is reached in regard to the nature 

 of the forces which caused the disturbance. 



2. Formation of Travertine and siliceous Sinter by the Vege- 

 tation of Hot Springs ; by Walter Harvey Weed. — This mono- 

 graph accompanies the Ninth Annual Report of the U. S. 

 Geological Survey (pp. 613-676), and has also been issued sepa- 

 rately. The abundant growth of algae in hot springs has been 

 noticed by many observers, but it has usually been heretofore re- 

 garded as an interesting biological fact rather than a matter of 

 any considerable chemical or geological significance. It is well 

 known that some water plants abstract carbonate of lime from its 

 solutions, and Cohn has shown that the growth of vegetation is a 

 factor in the production of travertine at Carlsbad. Beginning 

 with a study of the deposits about the hot springs in Yellowstone 

 Park, Mr. Weed shows that plant life is an important factor in 

 the deposition of the travertines, tufas and sinters from calcareous 

 waters, and that some of the more striking physical appearances 

 of these deposits are due to algae. Of even more chemical and 

 geological interest is the connection he shows between the depo- 

 sition of siliceous sinter from alkaline hot waters and plant 

 growth. Algae in great abundance and of varied and often bril- 

 liant colors are found on and in the forming sinter about the hot 

 springs in various parts of the world. Such deposits are espe- 

 cially extensive in Yellowstone Park, covering many square miles. 

 Heretofore, the separation of silica from hot solution about geysers 

 and hot springs has been supposed to be due to purely chemical 

 and physical causes, to reliel from pressure, cooling, evaporation, 

 and chemical reaction. Mr. Weed shows, that much of the silica 



