TRANSACTIONS OF SECTION B. 365 
drawing it through the holes of a wire plate, all the ordinary traces of crystalline 
structure disappear, but it still consists of minute granules of the C phase 
‘embedded in a matrix of the A phase. Further drawing at the same tempera- 
ture alters the mixed structure only slightly; for each temperature there 
appears to be a certain mechanical equilibrium between the phases. By lowering 
‘the temperature of drawing the C phase is further broken down into still 
-smaller granules, and the mixture approaches more nearly to the homogeneous 
A state. 
The observations were made on wires which had been as completely as 
‘possible converted into the A phase by wire drawing at the ordinary temperature, 
‘and in every case the tenacity observed was higher than any which has been 
-recorded by previous observers for equally pure metals. 
Gold. Purity—9,997 per 10,000. 
Tenacity at 288° absolute (15° C.) 15°6 tons per square inch. 
Fr 53° * (—180° C.) 22-4 ‘ 
Silver. Purity—10,000 per 10,000, 
Tenacity at 288° absolute (15° C.) 25:7 tons per square inch. 
Re PAD ne ae ea sO Oaks © 
‘Copper. (Conductivity 100%.) 
» Tenacity at 288° absolute (15° C.) 28-4 tons per square inch. 
"i Ae se 180". j560 
” 
” 
” 
_ The wires broken at the ordinary temperature showed no general stretching. 
“There was a slight extension of from 3 to | per cent., due entirely to a sharp reduction 
‘of diameter at the actual point of rupture. At the boiling-point of liquid air all 
the wires stretched from ]1 to 12 per cent. This stretching was uniform over the 
‘whole length between the grips. This was confirmed by exact measurements of 
the diameter at a number of points. 
The appearance of the fractured ends reveals several points of interest. In 
‘every case the copper wires showed the cupped formation at the extreme end. 
‘This formation is evidently due to the lower tenacity of the central core, due to 
‘the presence of gas- bubbles which have been drawn out into long tubes or cells. 
‘The silver wires occasionally showed a slight cupped formation, but in this case 
‘the gas bubbles to which it was due were glcbular, as if they had been evolved at 
‘the moment of fracture. The gold wires were practically free from sponginess, and 
‘the fractures were almost perfectly viscous. 
By drawing wires at the lowest possible temperatures it is hoped to obtain the 
‘ductile metals in their condition of maximum tenacity, and from the figures then 
available to be able to calculate the molecular cohesion at the absolute zero. 
3. On the Atomic Weight. of Chlorine. 
By Professor H. B: Dixon, F.2.3S. 
The author described the experiments made in conjunction with E. C. Edgar 
‘on the direct burning of a known weight of. hydrogen in a known weight of 
chlorine—the hydrogen, prepared by electrolvsis-of barium hydrate, being occluded 
in palladium, and the chlorine, prepared by: the electrolysis of fused silver chloride, 
‘being weighed in the liquid state. The resulting atomic weight is higher than 
‘that of Stas, but is in close agreement with the recent work of Professor Theodore 
JRichards. 
4. The Viscosity of Liquid Mixtures at the Temperature of their 
Boiling-points. By Dr. ALEXANDER FinpLay, 
The large amount of work which has recently been carried out on the viscosity 
~ of mixtures has not to any great extent been found capable of wide generalisation, 
~One reason for this is, no doubt, to be found in the choice of the temperature at 
which the viscosity of the mixtures was determined. Hitherto all investigations 
