155 
with holders in the test tubes D3 ~¢. The cylinders are taken out 
of the water after a definite time. : 
Then the contents are conveyed to a glass cup (Ay—7) by means 
of a pipette and by repeated rinsing of the cylinder with distilled 
water. The cups are made of small thin-walled glass spheres (diameter 
+ 1*/, em.) which were cracked off along a small circle, the rim 
being fused a little to prevent the glass from further cracking (see 
; fig. 3a). Then the bottom 
/ side was heated, till a flat 
bottom was formed, and a 
f En ap SS platinum wire was fused 
‘ j with both ends to the upper 
edge. A light glass tray (fig. 
a ¢ b 3b) may be laid on the cup, 
ce aes which rests on the rim of 
the cup with three glass rods, and serves to bear the weights. The 
cups Ay_3 therefore contain the original solution, the other four 
Ks: the diffusion rests. The ratio of the capacities of the diffusion 
evlinders was determined by weighing with mercury (for this purpose 
they were weighed empty, and after they had been filled with 
mereury and the superfluous mercury had been pressed off with a 
small glass plate they were weighed again). The filled cups were 
evaporated to dryness at 100° in an apparatus according to Victor 
Mever ©), and conveyed to a desiccator with strong sulphuric acid. 
The quantity of dissolved substance in the original solution of each 
cylinder /#y~; could then be calculated from the increase in weight 
Fig 
_ 
1) V. Meyer. Ber. der Deutsch. Chem. Gesellsch. 18. 2999. (1885). 
