296 



ago ; and a discussion followed as to the presence of additional 

 forms, some attributing it to insects, frogs, and other minor 

 aquatic animals, and others to the wild ducks that frequent this 

 brook through the summer season. 



W. A. MURRILL, 



Secretary pro tern. 



November io, 1908 

 The Club met at the American Museum of Natural History 

 and was called to order by Vice-President Burgess at 8:15 

 P. M. About 95 persons were present. 



After the reading of the minutes of the meeting of October 29, 

 Dr. N. L. Britton delivered the lecture of the evening on 

 " Trees of the Vicinity of New York ". The lecture was illus- 

 trated by lantern slides from the Van Brunt collection and was 

 of a popular nature. The trees were taken up in a biological 

 order, beginning with the gymnosperms, and the photographs' 

 exhibited illustrated both the general habit of the trees discussed 

 and details of their flowers and fruit. 



Marshall A. Howe, 



Secretary pro tevi. 



OF INTEREST TO TEACHERS 



The Camera Lucida for Class Demonstration 



By Robert Greeni.eaf Leavitt 



So far as I have seen, the use of the ca^nera lucida for purposes 

 of demonstration with classes, as now to be described, has not here- 

 tofore been put into print ; though it is altogether likely that others 

 beside myself have hit upon the device. The idea first occurred 

 to me when showing visitors at the laboratory the workings of 

 the compound microscope. The camera lucida always greatly 

 pleases the uninitiated by its magical power of bringing the pencil 

 into the field of the instrument, and of instantly conferring upon 

 the novice the skill of the draftsman. It occurred to me, while 

 exhibiting under the microscope and explaining some of the 

 objects one usually shows to these people, such as algae or stained 



