1895.] on the Barer Metals and their Alloys. 509 



chromium, vanadium, uranium, zirconium, tungsten, molybdenum and 

 titanium. [These were exhibited.] 



The question naturally arises : Why is the future of their useful- 

 ness so promising ? Why are they likely to render better service 

 than the common metals with which we have long been familiar ? It 

 must be confessed that as yet we know but little what services these 

 metals will render when they stand alone ; we have yet to obtain 

 them in a state of purity, and have yet to study their properties, but 

 when small quantities of any of them are associated or alloyed with 

 other metals, there is good leason to believe that they will exert a 

 very powerful influence. In order to explain this, I must appeal to 

 the physical method of inquiry to which I have already referred. 



It is easy to test the strength of a metal or of an alloy ; it is also 

 easy to determine its electrical resistance. If the mass stands these 

 tests well, its suitability for certain purposes is assured ; but a subtle 

 method of investigation has been afforded by the results of a research 

 entrusted to me by a committee of the Institution of Mechanical 

 Engineers, over which Dr. Anderson, of Woolwich, presides. We 

 can now gather much information as to the way in which a mass of 

 metal has arranged itself during the cooling from a molten condition, 

 which is the necessary step in fashioning it into a useful form ; it is 

 possible to gain insight into the way in which a molten mass of a 

 metal or an alloy, molecularly settles itself down to its work, so to 

 speak, and we can form conclusions as to its probable sphere of 

 usefulness. 



The method is a graphic one, such as this audience is familiar 

 with, for Prof. Victor Horsley has shown in a masterly way that 

 traces on smoked paper may form the record of the heart's action 

 under the disturbing influence caused by the intrusion of a bullet 

 into the human body. I hope to show you by similar records the 

 effect, which though disturbing is often far from prejudicial, of the 

 introduction of a small quantity of a foreign element into the 

 " system " of a metal, and to justify a statement which I made earlier, 

 as to the applicability of physiological methods of investigation to 

 the study of metals, In order that the nature of this method may be 

 clear, it must be remembered that if a thermometer or a pyrometer, 

 as the case may be, is plunged into a mass of water or of molten 

 metal, the temperature will fall continuously until the water or the 

 metal begins to become solid ; the temperature will then remain 

 constant until the whole mass is solid, when the downward course of 

 the temperature is resumed. This little thermo-junction is plunged 

 into a mass of gold, an electric current is, in popular language, 

 generated, and the strength of the current is proportional to the 

 temperature to which the thermo-junction is raised ; so that the spot 

 of light from a galvanometer to which the thermo-junction is attached 

 enables us to measure the temperature, or, by the aid of photography, 

 to record any thermal changes that may occur in a heated mass of 

 metal or alloy. 



