530 SUMMARY OF CURRENT RESEARCHES RELATING TO 



after different treatments. The effects of cold-working, annealing, etc., 

 are illustrated by particular examples. Time has an important' influence 

 on the effects of stress, since, though stress is instantaneous, strain re- 

 quires an appreciable time for its development, and may continue to in- 

 crease for months. Thus different stress-strain curves are obtained by 

 different rates of loading. Time effects are much greater in some metals 

 than in others ; the breaking-stress of zinc can be raised 50 p.c. by rapid 

 loading. The effects of repetitions of stress, and the work done to pro- 

 duce fracture, are among other points discussed. 



Internal Friction of Solids at Low Temperatures.* — C. E. Guye 

 andV. Freedericksz have determined the rate at which torsional vibra- 

 tions die away in silver, aluminium, gold, magnesium, iron, and quartz, 

 at 100°, 50°, 0°, - 80°, and - ll)6°C. For silver, aluminium, and iron, 

 the " coefficient of damping " diminishes with falling temperature, but 

 apparently does not tend to disappear entirely at the absolute zero. The 

 coefficient of elasticity of the metals becomes greater as the temperature 

 is lower. 



C. E. Guye and H. Schappert have made similar determinations on 

 copper, zinc, gold, nickel, palladium, and platinum. The coefficient of 

 damping was found to vary with the amplitude of the vibration. In 

 general, it cannot be said that this coefficient steadily decreases as the 

 temperature falls. It does not seem possible to arrive at any general 

 laws governing the value of the coefficient of damping. 



Novel Application of Alloys.:}: — Most alloys throughout a certain 

 range of temperature are partially solid and partially liquid. K. Friedrich 

 incorporates with partially solidified alloys in a pasty and workable con- 

 dition, solid substances in the form of powder. The examples described 

 are (1) an alloy of 90 p.c. tin and 10 p.c. copper heated to 500° C. and 

 allowed to cool to 220° C. Maintained at this temperature the alloy was 

 pasty ; a quantity of powdered blue glass was mixed with it, the mixture 

 pressed and allowed to cool, A polished section showed, a white metallic 

 ground sprinkled with blue particles. (2) An alloy of 98 p.c. lead and 

 2 p.c. antimony, mixed at 250° C. with 10 p.c. iron filings. Pressed and 

 cooled it gave a " hard lead." Possible uses for such pseudo-alloys are 

 discussed. 



Solubility of Gases in Metals and Alloys.§ — A. Sieverts and 

 W. Krumbhaar have determined the amount of various gases dissolved 

 by different metals and alloys, under varying conditions of temperature 

 and pressure. Experiments at very high temperatures were carried out 

 in porcelain tubes heated in a silundum tube resistance furnace. Nitro- 

 gen is insoluble in most metals, but forms nitrides with aluminium and 

 with iron. Sulphur dioxide begins to dissolve in copper at the melting- 

 point ; the solubility increases with the temperature, and is proportional 

 to the square root of the pressure. Numerous other facts are given in 

 the paper. 



* Rev. Metallurgio, vii. (1910) pp. 85-6 (1 fig.). 



t Comptcs Rendus, cl. (1910) pp. 9G2-4. 



t Metallurgio, vii. (1910) pp. 97-9. 



§ Ber. Deutscb. Cuem. Ges., xliii. (1910) pp. 893-900 (2 figs.). 



