TRANSACTIONS OF SECTION B. 459 
about ninety-four per cent. of cinnamic acid. The remaining impurities are almost 
insoluble in carbon disulphide, whilst the acid readily dissolves, and is left as a 
crystalline residue slightly discoloured on evaporation of the solvent. 
6. On Manganese Bronze. By P. M. Parsons.—See Reports, p. 378. 
FRIDAY, SEPTEMBER 21. 
The following Reports and Papers were read :— 
1. Report of the Committee on Chemical Nomenclature. 
See Reports, p. 127. 
2. Report of the Committee appointed for the purpose of investigating by 
means of Photography the Ultra Violet Spark Spectra emitted by 
Metallic Elements, and their Combinations under varying conditions.— 
See Reports, p. 127. 
3. Explosion of Carbonic Acid Gas—A Demonstration. 
By H. B. Dixon, M.A., F.C.8. 
4, Chemical Views on the Constitution of Matter. By Professor A. W. 
Wiuamson, Ph.D., FR.S. 
5. On the Atomic Weight of Manganese. By Professor Jamus Duwar, 
M.A., F.R.S., and Auexanver Scort, M.A., D.Sc. 
At the meeting of the Association in 1881 the authors gave an account of 
some preliminary determinations of the atomic weight of manganese, arrived at by 
the use of silver permanganate. This salt is very well fitted for such a purpose, 
as it is easily obtained in a state of great purity by crystallisation, and is not at 
all hygroscopic. The first and most direct method employed was reduction by 
heat alone, and finally ignition in a current of pure hydrogen. The reactions 
taking place are 
4AoMn0O, =2 (Ag,0,2Mn0,) + 30, 
2(Ag,0,2Mn0,) + 6H, =2Ag, + 4Mn0O + 6H,0. 
This method unfortunately did not give very concordant results, due probably 
to the retention of hydrogen and imperfect reduction of the oxide of manganese. 
Table I. gives the results of several experiments made in this way. 
TABLE I. 
Weight of Silver Weight of Residue 
Experi Permanganate Ag+MnO Oxy 
Sank eee ee Equivalent 
In Air In Vacuo In Air In Vacuo 
1 5°8688 58696 4-6320 4-63212 1:23748 227-673 
Il. 54981 54988 4:3358 4:33591 1:16293 226-965 
II. 76725 76735 6:0538 6:05395 1°61959 227°422 
LV’. 13:0997 13°10147 10:3179 1031815 2:78332 +| 225:943 
4 : 9°9104 9-91065 2°66925 226:22 
re EE LEC 99141 | 9-91435 | 266555 | 226-53 
