220 



SCIENCE. 



[N. S. Vol. XIV. No. 345. 



6. ' Summary of Analyses of ^the Massive Rocks of 

 Boulder County, Colorado ' : Chaeles S. Pal- 

 mer. 



7. ' The Indirect Weighing of Quantitative Precipi- 

 tates ' (by title): E. W. Thatcher. 



8. 'An Automatic Filter Washer' (20min.): J. 



M. PiCKEL. 



9. ' Some New Laboratory Furniture ' : Prof. 

 Lachman. 



10. ' Recent Developments in Physical Chemistry ' : 

 Wilder D. Bancroft. 



11. ' Proper Methods of Teaching Physical Chem- 

 istry ' : Wilder D. Bancroft. 



12. 'Some Points on the Teaching of Chemistry ' : 

 Charles S. Palmer. 



13. 'What Constitutes Instruction in Technical 

 Chemistry' (15min. ): Edward Hart. 



14 . ' Discussion of Methods used in Different Uni- 

 versities for Giving Instruction to Large Classes 

 in Elementary Laboratory Work ' : Wm. Mc- 

 Pheeson. 



15. ' The Teaching of Chemistry in Secondary 

 Schools' : Fredus N. Peters. 



16. ' Chemistry in Manual-Training High-Schools ' 

 (15min. ): Armand R. Miller. 



17. ' The Determination of Sulphur in Iron and 

 Steel '( 15 min. ) : Wm. A. No yes and L. Leslie 

 Helmee. 



18. ' Copper as allied to the Sciences, and its Com- 

 mercial Value ' (7 min.): W. S. Eberman. 



19. ' On the Decomposition of Sodium Nitrate by 

 Sulphuric Acid '—Part III. : C W. Volney. 



20. ' Quantitative Determination of Hydrofluoric 

 Acid' (3 min.): W. E. BURK. 



21. 'Methods of Standardizing Acid Solutions' 

 (15 min.): Cyril G. Hopkins. 



22. 'The Sulphohalides of Lead' (10 min.): Vic- 

 tor Lenhee. 



23. ' Hydrochlorated Mercury and Cadmium Sul- 

 phates' (5min. ): Chaeles Baskeeville. 



24. 'Evidences of the Probable Complexity of 

 Thorium ' ( 10 min. ) : Charles Baskerville. 



25. 'Constitution of Alloys?: J. A. Mathews. 



26. ' Cryoscopic Experiments with Sulphur' (12 

 min.): Alexander Smith. 



27. ' The Electrolytic Method applied to Uranium ' 

 (15 min.): LiLY Gavit Kollock and Edgar F. 

 Smith. 



28. 'The Electrolytic Determination of Molybde- 

 num ' (15 min.): Lily Gavit Kollock and Edgar 

 F. Smith. 



29. ' The Precipitation and Separation of Silver in 

 the Electrolytic Way ' (15 min.): W. H. Fulaveiler 

 and Edgar F. Smith. 



30. ' The Electrolytic Separation of. Mercury 



from Copper ' : C. Roscoe Shaw and Edgar F. 



S-MITH. 



31. ' The Identification and Properties of Alpha- 

 and Beta-Eucaine ' (15 min.): Charles L. Par- 

 sons. 



32. ' A Comparison of the Solubility of Acetylene 

 and Ethylene' (15 min.): Samuel Auchmuty 

 Tucker and Herbert R. Moody. 



33. ' On the Estimation of Urea in Urine ' ( 10 

 min.): John H. Long. 



34. 'On the Determination of Formaldehyde' (15 

 min. ) : A. G. Ceaig. 



35. A Modification of the Sulphuric Acid Test for 

 Formaldehyde in Milk ' (5 min.): A. GusTAV LUE- 

 BEET. 



36. ' The Synthesis of Ketodihydroquinazolins from 

 Anthranilic Acid ' (by title): August Heney GoTT- 



HELF. 



37. 'Researches on Nitrocellulose' (by title): G. 

 Lunge. 



38. ' The Reduction in an Alkaline Solution of 

 2.4.5. Trimethylbenzaldaziue ' (20 min.): E. P. 

 Haeding. 



39. ' Preparation of 2.5. Dimethylbenzaldehyde ; 

 the Estimation and Preparation of some of its Deri- 

 vatives ': EvEEHAET P. Haeding and Lilian 

 Cohen. 



40. ' A Study of the Chemical Composition of Meat 

 Extracts' (lOmin. ): H. S. Grindley. 



41. ' Chemical Changes Produced by the Action of 

 Bacteria' (10 min.): H. S. Geindley. 



42. 'Derivatives of Diphenyl Ether' (25 min.): 

 A. N. Cook. 



43. ' The Constitution of Azoxybenzine ' : Peo- 



FESSOE LACHMAN. 



44. 'The Action of Zinc Ethyl on Nitro and Nit- 

 roso Compounds — a Reply to I. Bewad ' : Pro- 

 fessor Lachman. 



45. ' Recent Developments in Organic Chemistry ' : 

 Professor Lachman. 



DISCUSSION AND CORRESPONDENCE. 

 PSEUDOSCOPIC VISION. 



The experiment described by Professor Wood 



(Science, August 2, p. 185) is always striking 

 and attractive when performed for the first time, 

 and he is probably only one of many who have 

 attained this binocular result independently. 

 I did so twenty years ago ; and my attention 

 was called to such phenomena more than thirty 

 years ago by the late Professor Joseph Le- 

 Conte. 



But the use of the unaided eyes for the at- 



