210 Mr. T. Graham on Liquid Diffusion applied to Analysis. 



of salt present in each jar was 10 grammes, which was found at 

 the end to be distributed as follows in the different sectional 

 strata of fluid, numbering them from the top downwards : — 



In the first or highest stratum, 0*103 and 0*]05 gramme of 

 salt in A and B respectively; in the second stratum, 0*133 and 

 0*125; in the third stratum, 0*165 and 0*158; in the fourth 

 stratum, 0*204 and 0*193; in the fifth stratum, 0*273 and 

 0*260; in the sixth stratum, 0*348 and 0*332; in the seventh 

 stratum, 0*440 and 0*418; in the eighth stratum, 0*545 and 

 0*525; in the ninth stratum, 0*657 and 0*652; in the tenth 

 stratum, 0*786 and 0*747; in the eleventh stratum, 0*887 and 

 0*875; in the twelfth stratum, 0*994 and 0*984; in the thir- 

 teenth stratum, 1*080 and 1*100; in the fourteenth stratum, 

 1*176 and 1*1.98; in the fifteenth and sixteenth strata together, 

 2*209 and 2*324 grammes. With differences so moderate in 

 amount between corresponding strata in the two experiments, 

 this method of observing diffusion may claim a considerable 

 degree of precision. 



In similar experiments made at the same time and temperature 

 with sugar, gum-arabic and tannin of nut-galls, the final distri- 

 bution of each substance was different in each, case, and the 

 results may be placed together in illustration of unequal diffusi- 

 bility, as exhibited by this method of observation. Two experi- 

 ments were made on each substance, as with chloride of sodium, 

 but the mean result only need be stated. 



Table I. — Diffusion of 10 per cent, solutions (10 grammes of 

 substance in 100 cub. centims. of fluid) into pure water, after 

 fourteen days, at 10° (50° Fahr.). 



No. of stratum 



Chloride of 









(from above 



sodium. 



Sugar. 



Gum. 



Tannin. 



downwards). 











1 



•104 



•005 



•003 



•003 



2 



•129 



•008 



•003 



•003 



3 



•162 



•012 



•003 



•004 



4 



•198 



'016 



•004 



•003 



5 



•267 



•030 



•003 



•005 



6 



•340 



•059 



•004 



•007 



7 



•429 



•102 



•006 



•017 



8 



•535 



•180 



•031 



•031 



9 



•654 



•305 



•097 



•069 



10 



•766 



•495 



•215 



•145 



11 



•881 



•740 



•407 



•288 



12 



•991 



1-075 



•734 



•556 



13 



1-090 



1-435 



1-157 



1-050 



14 



1-187 



1-758 



1-731 



1-719 



15 and 16 



2-266 



3-783 



5-601 



6-097 





9-999 



10-003 



9-999 



9-997 



