DEMONSTRATION MATERIAL IN GEOLOGY 81 



changes more vivid for the advanced student and for the man of general cul- 

 ture. We are all familiar with the device whereby a bud blossoms into a 

 flower on the screen before one's eyes, the pictures having been taken at slowly 

 spaced intervals by an automatic timing device. Could not this be applied to 

 geology, and thus forever do away with the popular belief in the everlasting 

 hills? 



"Where an island of sand and gravel is being attacked by a marine or river 

 current, for example, and within a day or a week or a month is totally de- 

 stroyed, the cinema could show it to us, dissolved in a minute. Where, after 

 heavy rains, a deep gorge is worn within a few days in some gravel deposit, 

 the machine would show it cut out as by a knife cutting into cheese. It is 

 difficult to foresee the lengths to which this demonstration could go. Doubtless 

 it would be too much to expect that photographs could be taken of glaciers at 

 regular intervals over a number of years, and then speeded up, showing us the 

 ice actually in the motion of flow." 



When a teacher sees an unusually fine bit of scenery in a motion-picture 

 theater he wonders if he could profitably use the picture in his class in 

 geology or physiography. As a result of such queries an organization, 

 called "The Society for Visual Education/' has planned and produced 

 films for educational purposes, not only for physiography, but for history, 

 civics, health and sanitation, mathematics, nature study, and physics as 

 well. In the film entitled "The study of a mountain glacier," President 

 W. W. Atwood gives a "chalk talk" in which he tells on the screen the 

 story of glaciers and icebergs, moraines, glacial valleys, etcetera. The 

 rent asked for this film is very reasonable, but how successful the film is 

 has not been learned. The fact, however, that the Society is sponsored by 

 well-known geographers is evidence that the films serve a useful purpose. 



Eestoeations 



No elementary student of geology can, with any degree of satisfaction, 

 reconstruct from their skeletons the external forms of extinct animals. 

 Because of this fact most teachers of historic geology have found it neces- 

 sary to show students not only the restorations of the skeletons of the 

 animals of the past, but also restorations of the animals as they looked 

 when alive. Many of the notable plaster restorations which have been 

 made by the staff of the American Museum of Natural History are sold 

 to educational institutions at a surprisingly low cost — an unselfish and 

 wise policy which other museums might well follow. The museum also 

 furnishes lantern slides of its restorations. There are also the excellent 

 restorations of Dean, Gilmore, Gidley, Lull, Scott, and Williston in this 

 country and those which appear in Hutchinson's "Extinct monsters and 

 creatures of other days"; Knipe's "Nebula to man," Jaekel's "Wier- 



VI — Bull. Geol. Soc. Am., Vol. 33, 1921 



