SIXTH ANNUAL RECEPTION. 85 



27. Hertz Wave Apparatus. Exhibited by A. E. Lawrence. 



28. Effect of an Alternating Current upon the glowing 



filament of an incandescent lamp producing nodes and 

 loops as in Melde's experiments. 



Exhibited by W. C. Peckham. Adelphi College, 

 Brooklyn. - 



29. Mercury Vacuum Pump ; new short form, designed by 



Boltwood, which requires only 5 lbs. of mercury ; will 

 exhaust a vessel of one liter capacity to a cathode ray 

 vacuum in 25 minutes. 



30. Polariscope, new half shade instrument with triple field of 



vision, adopted as United States Standard for sugar 

 polarization. 



31. Colorimeter, according to Lovibund. An apparatus for 



the recording and comparison of colors. 



32. Junke's Reading Lens for thermometers. 



23. X-Ray Tube for 16-inch spark. For induction or static 

 machine. No platinum used at cathode. 



34. Glass Prisms, hollow, plates fused together to stand all 



acids and alkalies. 



35. New Reverberatory Shade and Chimney for Welsbach 



incandescent light. 



Nos. 29 to 35 exhibited by Eimer & Amend. 



36. Audimeter. An instrument for the production of standard 



units of sound intensity, and for the establishment of 

 corresponding units of sensitiveness and defectiveness 

 of hearing. Exhibited by Alfred G. Compton. 



2,y. Electrical Interrupter for Helmholtz's acousdc appar- 

 atus and other uses. Exhibited by Alfred G. Compton. 



38. Focusing Arc Lamp. Exhibited by Alfred G. Compton. 



39. a. Chromo-Photographs on paper, of life scenes, instantan- 



eous. 

 d. Stereoscopic views on glass. 



Exhibited by Charles L. A. Brasseur. 



