j 8 i 
sen a* being typical of extensive classes rather than as being 
connected with one another in immediate chemical relation. 
They were : 
Water; Alcohol; Acetic Acid; Acetic Ether; Butyric Acid ; 
Oil of Turpentine ; Benzol; Glycerine and Mercury. 
The several liquids were allowed to drop from the same 
platinum cup. The arrangement of the apparatus was quite 
similar to that described in T. the ivory ball being replaced by 
the platinum cup, and the overflow of the cup being deter- 
mined by strips of paper bent. over its edge. The last ease, 
mercury, is the only one which requires some explanation. 
A few years ago (. noticed a fact widen has probably been ob- 
served by others, but of which I find no mention: namely 
that mercury which holds even a very little sodium in solu- 
tion has the power of “ wetting” platinum in a very remark- 
able manner. The appearance of the platinum is quite simi- 
iar to that of amalgamable metals in contact with mercury, 
but the platinum is in no wise attacked. Further, the amal- 
gam may be washed off by clean mercury and the latter will 
also continue to adhere equally closely to the platinum. All 
the phenomena of positive capillarity are presented between 
the two. The surface of the mercury in a platinum cup so 
prepared is quite concave; and a basin of mercury maybe 
emptied if a few strips of similary prepared platinum foil are 
laid over its edge : just in the same way as a basin of w ater 
may be emptied by strips of paper or cloth; and under the 
same conditions, namely that the external limb of such capil- 
lary siphon be longer than the internal one. 
I generallv use this curious property of sodium amalgam 
for cleaning platinum of vessels. It enables us now to exa- 
mine the size of drops of mercury under conditions similar to 
those which obtain in the ease of other liquids. ■■ 
# In regard to the above mentioned property of sodium, t,bc follow - 
im» observations may be of interest. At lirst, t be explanation naturally 
sim 'esta itself that the effect wrought hv the sodium may be due to an 
ubeorbtion of oxygen in consequence of the Oxidation of the sodium, 
