55 



19. Original Diagrams of Track Inspections, showing the 



comparative undulations on light and heavy rail sections. 



20. Condensed Diagrams of the Inspection of the N. Y. 



C. & H. R. R. R. 



21. Condensed Diagrams of the Inspection of the Boston 



& Albany R. R. 



22. Two Cuts of Rails, Showing the General Law of 



THE Compound Fracture under the "Drop," the base 

 breaking first, then the head as an independent member. 

 In a few cases the head remained unbroken. 



23. Six Cuts, Showing Ingots, the Fracture of Broken 



Ingots, the " Drop" and Drop Tests of Rails. 



24. Micrometric Apparatus to Measure the stress on 



the Rails Under a Locomotive. 



25. Autographic Apparatus to Measure the Elongation 



AND Compression of the Base of Rails in the Track 

 Under Moving Trains. New. 



Nos. 19 to 25 are exhibited by P. H. Dudley. 



26. Apparatus for Teaching Elementary Physical Sci- 



ence IN Schools. Devised and exhibited by John F. 

 Woodhull, Teachers College. 



27. Telescopes Belonging to Spectroscope, Lenses of 



Quartz and Calcite, and New Thallium or Huggins 

 Prism. 



28. Landolt new Polariscope. 



29. FuESS NEW Petrographic Microscope Stand and Ac- 



cessories. 



30. Apparatus for Furnishing Monochromatic Light for 



the Goniometer. 



Nos. 27 to 30 exhibited by Miss Hitchcock. 



31 . Resonant Tube and Tuning Fork, with electrically main- 



tained vibrations. 



