the Motion of Spheres through Li'quidi 

 Table I. 



761 



Capillary. 



Radius. 



Length. 



" h." 



Time. 



Mass. 



/*• 



I 



•09275 



74-35 



SG-9 



600 



10-241 



•6958 



I 



»> 



>> 



»> 



j> 



10263 



•6943 



I 



„ 



>» 



,, 



„ 



10-289 



•6953 



I 



,, 



,, 



230 



,, 



6387 



•6954 



II 



•05624 



6250 



39-5 



1000 



2-946 



•6939 



II 





n 



,, 



,, 



2-933 



•6971 



" 



,, 



>> 



„ 



>> 



2-943 



•6946 



II 



,, 



,, 



,, 



„ 



2-929 



•6980 



II 



5> 



» 



>i 



» 



2-937 



•6962 



Average /* =0-6956 ±'0024. 



determined from its computed volume as well as by weighing 

 in air and in water. The average density thus determined 

 was 9-718 + -003. 



This metal melts at about 82° (J. and is quite fluid at the 

 temperature of boiling water. It was placed in a small test 

 tube drawn out to form a short capillary, and the whole 

 suspended in a glass tube about 70 cm. long and 3 cm. in 

 diameter. The large tube was then filled with water, and 

 heat was applied in such a way that the upper end was kept 

 at 100° 0. while the lower end was at about 60° C. The 

 molten metal was forced out by compressed air, and settled 

 in the form of spray, the drops being sufficiently cooled to 

 maintain their spherical shape by the time they reached the 

 bottom. The success of this method depends on the rela- 

 tively slow motion of the spheres, and on the slight tempe- 

 rature gradient of the water through which they fall. The 

 slow and uniform cooling tends to produce homogeneity of 

 structure, while the low velocities allow the retention of an 

 almost perfectly spherical shape. With a capillary of the 

 proper size a single casting gave a large number of spheres 

 with radii from "002 cm. to *1 cm. Many of these spheres 

 showed surface pits, but from the large number prepared it 

 was not difficult to pick out sufficiently perfect specimens 

 of any desired size. Check experiments with badly pitted 

 surfaces showed, however, that no appreciable change in 

 velocity could be attributed to these surface irregularities. 



In a series of observations with these spheres the tempe- 

 rature was maintained as nearly as possible at 21 0, 4 0. At 

 this temperature the density of the colza oil is '9166. In 



