On the Fluid Density of certain Metals. 



361 



Six experiments were made with the oncosirneter* on copper; 

 four of these were made with cast copper balls 2 J" diameter, 

 one with a cast-iron turned ball 2^ // in diameter, and one with 

 a copper ball Z" in diameter. The first four were made with 

 a spring that lengthened \ inch per ounce troy ; the last two 

 with a more sensitive spring, giving \ inch elongation per 

 ounce troy. It will be seen by the accompanying table that 

 the fluid density does not vary much, although, as has just 

 been stated, the conditions were varied. 



No. of 

 expt. 



Diameter 



of ball, 



in inches. 



Weight, in 1 ifi 

 troy ounces,^ f 8 



including l bal | inclu . 



the stem , ^ h 

 for attach- , | 

 ment. 



Sinking 

 effect on 

 first im- 

 mersion, 

 in troy 

 ounces. 



Deduced 



specific gra- 

 vity of fluid 

 metal. 



Eemarks. 



37. 



2-25 



26-357 8-23 



nil. 



8-23 | 



Copper ball 

 in fluid 

 copper. 



38. 



do. 



27-005 



8463 



•2 



8-4 



do. 



39. 



do. 



26-25 



8-288 



•5 



8-13 



do. 



40. 



do. 



25-923 8-281 



•2 



8-217 



do. 



41. 



do. 



22-186 7-02 (iron) 



Floating effect 

 35 



8-127 { 



Iron ball in 

 fluid copper. 



42. 



3 



64-237 8-01 



i 



Sinking effect 

 3-0 



8-2 I 



Copper ball 

 in fluid 

 copper. 









Mean 



.. 8-217 









Specific gravity of soli 



\ copper 



.. 8-8 



1 



1 



The mean of these results gives 8*217 as the density of fluid 

 copper. This metal melts at a temperature which exceeds 

 1000° C, and, when melted in air, absorbs oxygen. "We 

 found, for this reason, that it was not possible to obtain trust- 

 worthy results by Mallet's method, even though the cone was 

 filled with an atmosphere of coal-gas. 



* A description of this instrument was published in the Journal of the 

 Iron and Steel Institute, part 2, 1879, p. 41$. 



