which these experiments were performed is very similar to 

 those twofold bent glass tubes employed by Stephen Hales, 

 when he endeavoured to determine the force with which the 

 crude sap ascends in the vine : the end of the shank must here 

 however be blown out in a funnel or bell shape, in order thus 

 to present a larger surface of membrane to the endosmosis. In 

 the first bend of the tube an aperture must be made, which may 

 be closed by a glass stopper, through which the various fluids 

 employed for the experiments may be poured, and a scale is 

 fixed to the outer long shank. Now when the endosmosis is 

 allowed to proceed in this instrument, the fluid contained in it 

 rises by the absorption of the external water; and if some 

 mercury has been placed in the two exterior shanks of the 

 glass tube, this mercury is pressed downwards in the inner 

 shank by the raised column of air and forced upwards in the 

 exterior shank, which can then be nicely measured by the 

 scale there fixed. By similar observations M. Dutrochet 

 arrived at the result, that the force with which water is ab- 

 sorbed in the endosmosis, is more powerful according to the 

 proportion in which the density of the fluid in the interior of 

 the instrument stands to the exterior water. Sugar solu- 

 tions of 1 '035, 1*070, and of 1*140 spec. grav. were prepared; 

 the latter consisted of about one part of sugar and two of water. 

 The excess in density of these fluids above the density of the 

 water was in the proportion of 1, 2, 4. The solution of sugar 

 of 1*035 spec. grav. sucked up into the instrument so much 

 water during twenty-eight hours, that the column of mercury 

 was raised 10" J"'. The second solution caused the mercury 

 to rise in thirty-six hours to 22" 10"' ; and the third solution of 

 1*140 density, in forty-eight hours to45" 9"'. The observations 

 were made at a temperature of 16^ Reaum., and it is evident 

 from them, that the force of the endosmosis is subject to the 

 same law as its velocity. Similar experiments w r ere now per- 

 formed with several other substances; and M. Dutrochet ar- 

 rived at the result, that a solution of albumen exhibits the 

 most powerful endosmosis; after this sugar, then gum, and 

 last and weakest of all, gelatin ; these substances indeed, with 

 respect to the strength of their endosmosis, are expressed in 

 numerals in the following proportion : solution of albumen 12, 

 sugar 11, gum 5'l,and gelatin 3. 



