Disintegration of Metals at High Temperatures. 277 



given pressure, in air. Numerous sets of observations were 

 taken ; it is extremely difficult to get the effects definitely 

 marked, but the curve in tig. 3 shows the chief features of 

 the results which were always obtained. Fig. 3 represents 

 the relation between the temperatures and the minimum 

 expansions required to catch the nuclei given out at those 

 temperatures, for a pure platinum wire containing hydrogen, 

 that is, for a wire whose behaviour is represented by fig. 2 b. 



Fisr. 3. 



I. COO 



ISO 



| MOO 



1 



1.050 



<> — E 



J.OOC 



300 400 500 SCO 700 800 1500 



T£A1P£/?/l TUFtES (fi£Q/?££S CE/VT/GtftA OE) 



It is noticed from the curve that : — 



1. No nuclei are obtained at a temperature below 350° C. 

 in air at atmospheric pressure. 



.2. The nuclei caught at this temperature are of a maximum 

 size represented by an expansion of .1/119 and a 

 minimum represented by an expansion of 1 , 152 J and 

 higher expansions beyond 1*152 do not produce any 

 more drops. 



3. As the temperature is raised, nuclei of the same size, 



and of larger sizes, are produced. 



4. At a temperature of about 500° C, in addition to the 



nuclei caught with expansions between 1*02 and 1'152, 

 other nuclei begin to be produced, which are first 

 caught at 1'188, but when the wire has reached a 

 temperature of about 600° 0. they are caught by an 

 expansion of 1*016. 



5. No matter how hot the wire is made, no nuclei are 



caught by an expansion of 1'014. 



