SS ee ee a his Seer en (Ugh ile Seah eee a Leg Le a eee SS Nc a 0 = i am Gaal eR yeh Nl ea ade 
E. S. Morse—Classification of Mollusca, etc. 19 
Distance fallen being 5 in., the reduced deviations are given 
23°5° gmc 16°3°, 138°, , 124°, 11:6°, 108 Bo je Bl? "86°, 
84°, 81° , 79°, 84 *, 84 © 7:85°, 74°, 75°, 66°, 7-22, 7, 6'8°. 
A pcan action was observed with unwaxed silk, This 
might be accounted for by saying that the mass of silk and wax 
becoming compacted is then a better conductor of heat than be- 
fore, and that the temperature of the couple is thus lowered by 
the short but necessary contact with the ball; but the compara- 
tively small effect which is produced even by continued contact 
with the ball shown in tables 6 and 8 prove that this supposition 
is untenable. 
The larger deviation must then be attributed to the sliding of 
the particles of silk and wax over themselves, this taking place 
to a much greater extent in the first twenty falls than afterward. 
After the minimum point has been reached, if the couple is laid 
bare and rewound, the same large deviations are obtained, show- 
ing that they are not due to an alteration in the couple itself. 
Finally, it is remarkable that a much smaller mechanical force 
m3 lied directly to the couple in the shape of friction, produces 
isproportionately large deviation ; thus drawing the wooden 
pie of a lead-pencil once over the naked junction with a force 
less than would be ee iy the ball falling 1 inch gave a 
deviation of 18-25° 
It is hardly necessary to add, that the deviation of the needle 
was in all cases in the same direction as though heat had been 
applied to the juncture of the thermo-electric couple 
New York, Feb. 22, 1866, 
Art. IIl.—A Classification of Mollusca, based on the “Principle 
of Cephalization ;” by Epwarp 8. Morse. '—With a plate. 
R beeoming acquainted with the perfect unity of plan in 
ee Radiata and the connected series of homologies, running 
through the whole branch, (as demonstrated by Prof. Agassiz 
in his private lectures) my interest was excited to discover, if 
inding the universality of vertebration among the Vertebrata, 
of articulation among the Articulata, and similarly of radiation 
among the Radiata, I could not but believe that in the Mollusca 
* 
some plan lay hidden, which, when unfolded, would as | : 
convey their type, and unite them all, as in ‘the other. 
' Proc, of Easex Institute, iv, p. 162. 
