June 29, 1900.] 



SCIENCE. 



1033 



'long-shore lagoon), banks (in the N. C. sense 

 of a sand reef, and also in the fisherman's sense 

 of fishing grounds on a shallow sea floor) whale- 

 back and horseback (Me.). The list might be 

 extended still further. 



MORAINES OF SOUTH DAKOTA. 



The account of the ' Moraines of southeastern 

 South Dakota and their attendant deposits ' by 

 Todd (U. S. Geol. Surv., Bull. 158, 1899) is 

 another example of those remarkable correla- 

 tions between glacial action and existing topog- 

 raphy by which so much light has been thrown 

 on modern physiographic study in recent years. 

 The outer (Altamont) moraine marks the 

 border of an irregularly lobate glacier lying be- 

 tween Missouri and Big Sioux rivers, whose 

 advance was retarded where preglacial hills 

 (outliers of Cretaceous and Tertiary strata) 

 stood in its way ; here the moraine rises in an 

 interlobate upland which terminates inward 

 (towards the glaciated area) in a strong cusp, 

 as in Turtle and Turkey hills ; the rim of the 

 upland is incised by broad channels of glacial 

 waters which flowed from the ice, and the axis 

 of the upland is trenched by the trunk stream 

 that resulted from the confluence of these ice- 

 water branches. The broad lobate glacier 

 seems to have invaded the preglacial course of 

 the Missouri, which therefore rose as a lake 

 (Old Red lake) just above the entrance of White 

 river from the western plains ; the lake level 

 being recorded by a large delta built by this 

 river. The outlet 9f the lake was along the 

 southwestei-n margin of the ice where a new 

 channel has been cut from the mouth of White 

 river to that of Niobrara river. At a later 

 stage, a second moraine (Gary) was formed 

 around a reduced ice.lobe; whose area is roughly 

 marked by the space between the James and 

 Vermillion rivers. The floor of the ice lobes is 

 now a smoothly undulating plain of till or silt, 

 free from buttes and incised by narrow stream 

 channels. 



BULLETIN OF THE AMERICAN BUREAU OY 

 GEOGRAPHY. 



E. M. Lehnerts, of the State Normal School, 

 Winona, Minn., with nine associate editors, 

 has lately issued the first number of a quarterly 

 bulletin with the above' title, as an aid to the 



teaching of school geography. A report of a 

 committee on lantern slides, illustrated with 

 small prints of thirty views, is the most original 

 feature of the issue, which is otherwise largely 

 occupied with general articles on time-honored 

 subjects. Four writers treat of the ' Educa- 

 tional value of geography,' 'What to teach in 

 geography,' ' Geography as a basis for correla- 

 tion ' and ' Concrete geography.' Physiography 

 has four articles by Collie, Tarr, Kiimmel and 

 Moore, containing some specific suggestions re- 

 garding equipment and some illustrative ex- 

 amples, along with generalities. An article 

 on a special topic, the ' Points of the Compass,' 

 is at fault in neglecting the sun's noon culmi- 

 nation as the simplest means of determining 

 the local meridian and the cardinal points, and 

 in asserting that ' ' the north star is thus the 

 only satisfactory, because the only fundamen- 

 tal starting point for determining direction." 

 A committee on exchange of products, with 

 Philip Emerson of Lynn, Mass., as chairman, 

 promises to be a practical aid to isolated 

 teachers. 



W. M. Davis. 



THE STUDY OF ELECTRICAL PRESSURE. 



Professor John Trowbridge, of Harvard 

 University, contributes the following account of 

 his work on electricity to the Harvard Graduate 

 Magazine : 



The remarkable development of the practical 

 employment of electrical phenomena has put 

 physical laboratories at a certain disadvantage ; 

 for the electrical engineer and the assistants in 

 the great electrical companies have it in their 

 power to experiment with electrical currents of 

 far greater strength than it is possible to ob- 

 tain in a university laboratory. While the col- 

 lege professor might perhaps employ a hundred 

 horse-power and its equivalent in electrical 

 energy, the electrical engineer has at his com- 

 mand many thousand horse-power. He can 

 study the effect of tremendous currents in 

 breaking up chemical compounds and in form- 

 ing new compounds. He can investigate the 

 phenomena of electro -magnetism on a great 

 scale. There is, however, one field in which 

 the college professor can enter the electrical 

 field on more than equal terms as regards 



