15° 



REPORTS ON INVESTIGATIONS AND PROJECTS. 



Series II.— MnBko : MgBr. 



Number of 

 analvsis. 



16 



17- 

 18 



19- 

 20. 



21 



22. 



23- 



24 



25- 



26 



27 



28. 



29 



30 

 3i- 



Average . 



Sample 



of 

 MnBrn. 



A 



A 

 A 

 A 

 C 

 C 

 C 

 A 

 A 

 B 

 B 

 B 

 C 

 D 

 D 

 D 



Weight of 



M11 Br, 

 in vacuum. 



Weight of 



AgBr 

 in vacuum. 



Atomic 



weight of 



Mn. 



Grams. 



5-5S4I8 



5-63433 



6-53745 



4.81006 



4.88098 



5.63220 



6.52627 



5.79926 



3-598" 

 5-16335 

 3.92227 



4-49I59 

 3.60073 



4-77393 

 3 57660 



5-69973 



Grams. 

 9.76578 

 9.85362 

 II.43318 

 S. 41223 



8.5365S 



9-85025 

 11.41309 



10.14223 



6.29286 

 9.02975 



6.85984 

 7.S55S7 



6.29731 

 8.34919 



6.25572 



9.96845 



54 

 54 

 54 

 54 

 54 

 54 

 54 

 54 

 54 

 54 

 54 

 54 

 54 

 54 

 54 

 54 



959 

 956 

 954 

 953 

 945 

 949 

 964 

 953 

 946 

 961 



945 

 936 

 951 

 9+9 

 930 

 947 



54-95" 



Average, rejecting analysis 30. 

 Average of Series I and II 



54 951 

 54 953 



MnBr 2 :2Ag. 



Average of analyses with — 



Sample A of MnBr, 54-957 



MnBr 2 54-957 



MnBr 2 54-958 



MnBr 3 54 948 



Ag 54-958 



Ag 54-956 



Ag 54-955 



B 

 C 

 D 

 A 

 B 

 C 



MnBrji-JAgBr. 



54-954 

 54-947 

 54-952 

 54-948 



The close agreement of the averages of Series I and II and of the 

 averages of analyses with different samples of material leaves no 

 doubt that the atomic weight of manganese lies very near the average 

 of Series I and II, 54-953 (Ag = 107.930). 



Gombergf, Moses, University of Michigan, Ann Arbor, Michigan. 

 Grant No. 153. Study of triphenyhnethyl and analogous com- 

 pounds. (For first report see Year Book No. 3, page 106.) $500. 



Abstract of Report. — Work under this grant was carried on with 

 the assistance of Dr. Iy. H. Cone. The influence of sunlight upon 

 solutions of triphenylmethyl was first investigated, as this influence 

 was found to be a disturbing factor in all our work. It was found 

 that in presence of certain solvents triphenylmethyl is reduced under 

 the influence of light to triphenylmethane. All our further work 

 was therefore carried on in absence of sunlight. A complete study 

 of the combinations of triphenylmethyl with the different classes of 



