Mat 21, 1909] 



SCIENCE 



829 



many of the varieties analyzed contained admix- 

 tures of foreign substances. 



The Chemical Work of the U. 8. Geologioal Sur- 

 vey: Feank Wiggleswobth Claeke, of Wash- 

 ington. 



An account of the admirable chemical work of 

 the Greological Survey Laboratory, of which Pro- 

 fessor Clarke is the chief, with a review of the 

 more important results of this work. 

 Recent Work on the Physios of the Ether: Paul 

 E. Heyi., of Philadelphia. 



Considerable interest has been taken of late in 

 the question as to whether the ether is or is not 

 a dispersive medium with regard to light. The 

 work of the speaker, published about a year and 

 a half ago, leads to the conclusion that any dis- 

 persion in the ether must be less than one part 

 in 250,000. Since that time others have arrived 

 at the conclusion that there exists a dispersive 

 effect of much smaller magnitude, about one part 

 in a million. There seems to be no doubt of the 

 correctness of their observations, but it is not 

 clear that it is to be attributed to a real dis- 

 persive effect in the ether. It is more likely that 

 it is due to tidal phenomena in the atmosphere 

 of the variable stars used as sources of light in 

 the experiments. 



The Effect of Bleaching Powder upon Bacterial 

 Life in Water: Professor William Pitt Mason, 

 of Troy, N. Y. 



The extraordinary bactericidal effect of free 

 chlorine or of bleaching powders used in minute 

 quantities in drinking waters was described and 

 it was suggested that an emergency plant for the 

 manufacture of chlorine for this purpose should 

 be attached to the municipal water supplies. 

 The Detonation of Gun Cotton: Professor Chaeles 

 E. MuNEOE, of Washington. 

 In the use of gun cotton in mines and torpedoes 

 advantage is taken of the discovery of Mr. E. 0. 

 Brown that gun cotton which is completely satu- 

 rated with water may be detonated by the de- 

 tonation of dry gun cotton in direct contact with 

 it used as a " priming charge," thus securing a 

 large margin of safety for the naval vessels carry- 

 ing the explosive. Wet gun cotton containing as 

 high as 35 per cent, of water has been shown to 

 be a more efficient rupturing and shattering ex- 

 plosive than dry gun cotton, but the quesrtion of 

 how much water the discs of priming gun cotton 

 may contain to be efficient was the object of the 

 research detailed in this paper. The primer was 

 in all cases fired by the service detonator contain- 

 ing 36 grains of mercuric fulminate. The results 



show that detonation of the entire charge was 

 effected in every case in which the primer con- 

 tained less than 12 per cent, of moisture, and 

 occasionally was complete in cases where the 

 moisture ran as high as 15 per cent, and there- 

 fore that such gun cotton primers containing not 

 more than 12 per cent, of moisture, fired by means 

 of a detonator containing 36 grains of mercuric 

 fulminate may be relied upon to detonate wet gun 

 cotton with which they are in contact. 

 The Toxodontia: Dr. W. J. Sinclair, of Princeton. 

 South American Fossil Catacea: Dr. Peedekick 



W. Teue, of Washington. 



Dr. True remarked that in connection with a 

 revision of the fossil whales and porpoises of the 

 United States he had had occasion to examine 

 various specimens from Patagonia, including some 

 belonging to Princeton University and to the 

 American Museum of Natural History. Among 

 the former, he found a skull of a new genus allied 

 to the large porpoise of the Amazon River, known 

 as the inia, but very much larger. The principal 

 specimen from the American Museum of Natural 

 History was a very finely preserved skull of a 

 little-known genus, Diochotichus. This skull is 

 remarkable in possessing large openings through 

 the ethmoid plate, indicating that this porpoise, 

 unlike modem forms, probably possessed a brain 

 with an olfactory lobe and well-developed olfac- 

 tory nerves, and hence, was endowed with a good 

 sense of smell. 



The Patagonian fossil cetaceans thus far known 

 are from the provinces of Santa Cruz and Chubut, 

 and are believed to belong to the Tertiary Epoch. 

 At all events, some of the genera are the same as 

 those found in the Miocene formations of Mary- 

 land, New Jersey and other Atlantic coast states. 



Some of the Patagonian forms belong to families 

 still represented in South America by living spe- 

 cies. Others represent families no longer existing. 

 The fossil fauna includes sperm whales, various 

 forms allied to the inia, others allied to Squalo- 

 don, and at least one species of whalebone whales, 

 allied to the finbacks, but no ziphioid, or beaked, 

 whales nor any true dolphins have been found. 

 The Destruction of the Fresh-water Fauna, of 



Western Pennsylvania: Dr. Aenold E. Oet- 



MANN, of Pittsburg. 



Tlie fresh-water fauna forms part of our nat- 

 ural resources. That it has been injured and 

 partly destroyed by the advance of civilization is 

 well known, but it is not realized how far the 

 destruction has advanced. Since a number of 

 fresh-water creatures are of economical value 



