27 



3. Bheak-circuit Attachment for Pendulum. Exhibited 



by Prof. W. Hal lock, Columbia University. 



4. Pendulum, Adjustable Period. Exhibited by Prof. W. 



Hallock, Columbia University. 



5. Torsion Pendulum of Adjustable Period. Exhibited 



by Prof. W. Hallock, Columbia University. 



6. Improved Apparatus for Determining Battery Re- 



sistance ; Mance's method. Exhibited by W. S. Day, 

 Columbia University. 



7. Photographed Micrometer Ocular. Exhibited by Wal- 



lace Goold Levison. 



S. Apparatus for Showing Phosphorescence. Exhibited 

 by Wallace Goold Levison. 



9. Stremmatograph and Records. Exhibited by P. H. 



Dudley. 



10. Simple Photospectrograph with Negatives. Ex- 



hibited by F. L. Tufts, Columbia University. 



11. Bausch & LoMB Microscope Stand with Special Arm 



FOR MiCROMETRic MEASUREMENTS. Exhibited by P. 

 H. Dudley. 



12. New Form of Thermometer for Subterranean Tem- 



perature Work. Exhibited by Prof. W. Hallock, 

 Columbia University. 



1 3 . Series of Lantern Slides Illustrating a New Method 



OF Coloring by which Uniformity of Tint and 

 Definition of Outline is Obtained. Exhibited by 

 C. C. Trowbridge, Columbia University. 



14. Set of Scales Provided with Different Types of 



Vernier, used in the Physical Laboratory, Columbia 

 University. Exhibited by C. C. Trowbridge and H. S. 

 Curtis, Columbia University. 



15. Schone's Apparatus for Mechanical Analysis, and 



Specime?^s Tested by it. Exhibited by Dr. H. Ries, 

 Columbia University. 



