266 Wisconsin Academy of Sciences, Arts and Letters. 
Taking into consideration the pressures developed while the 
apparatus is kept nearly at a constant temperature, we find 
that according to No. 57 the osmotic pressure of the 0.125 nor¬ 
mal solution of LiCl is 51.2 cm. at 19.0,° and according to No. 
58 it is 54.2 cm. at 19.6.° Again, according to No. 59 the os¬ 
motic pressure of a 0.125 normal sugar solution is 9S.3 cm. at 
20.0,° while according to No. 60 it is 91.8 cm. at 21.0.° Even 
in these cases the agreement of the duplicates leaves much to be 
desired, for the differences in pressure observed can hardly be 
due to the slight differences in temperature. They are more 
likely due to individual differences in the membranes used, and 
to the fact that even with constant stirring, it was not quite 
possible to keep the liquids in immediate contact with the mem¬ 
brane of perfectly uniform concentration on each side. These 
difficulties have already been discussed at length above. There 
can be no doubt, however, that the results obtained are approx¬ 
imately the osmotic pressures of the solutions in question under 
the conditions of the experiments. 
The effect of stirring is clearly shown by a comparison of ex¬ 
periment No. 54 where the highest osmotic pressure of a 0.125 
normal sugar solution was found to be 6'2.4 cm. at 17.5° with¬ 
out stirring, and the result recorded in No. 59, where with stir¬ 
ring the osmotic pressure was found to be 98.3 cm. at 20.0.° 
Taking the highest values found, namely 54.2 cm. for 0.125 
normal LiCl solution at 19.6° and 98.3 cm. for 0.125 normal 
sugar solution at 20.0,° we note ( 1 ) that the electrolyte gives by 
far the lower pressure, and (2) that neither the LiCl nor the 
sugar give anywhere near the pressure called for by the gas 
laws, according to which a 0.125 normal sugar solution ought to 
give a pressure of approximately three atmospheres (228 cm. 
Hg) at 20. 5 Further, it will be recalled that a 1.2 per cent 
solution of sugar yielded practically no osmotic pressure at 0,° 
whereas according to the gas laws it ought to have produced 
about 0.8 of an atmosphere. And again, 0.05 normal solution of 
AgNO s yielded no osmotic pressure, whereas according to the 
gas laws it ought to have produced over an atmosphere. 
Further, the changes of pressure above recorded as caused by 
changes of temperature are so very much greater than they 
