Chemistry and Physies. 453. 
the polarization of the metals above mentioned, in solutions 
he most m 
alternately put in contact wi ith this battery and with a micro- 
maximum given the electrodes. By means of a peor bone 
galvanometer or an electrometer, this difference of potential was 
measured. When the electrodes were of distilled zinc Dlasedii 
zinc sulphate solution, and called unpolarizable, charged with an 
- electromotive force of one volt, three contacts of the key gave 
th ntacts. 
bra ie system on ea co aad, thei thr iree or four contacts, 
the i 
curves whose abscissas represent the differences of potential of 
the charging source and whose ordinates are the differences por 
to the condenser by the electrodes, it appears that for the metals 
and solutions studied, polariz zable systems are produced under 
those circumstances whose difference of potential increases con- 
tinuously from zero up to the point of decomposition of the 
sreotrolyse into its elements. Thus with electrodes of magne- 
n alies, this electromotive force reaches 3°8 volts and 
with aluminum in aci jie lated water, more than’ 4 volts. spi re- 
senting by Try the energy of formation of an electrolyte ¢ 
and pn and th 
shown follows a continuous law of variation, this chemical work 
in value from Tpy to zero; i. e., et ween the point of 
electrolysis and the neutral condition of the electrodes; by 
giving at the lower limit the equation Tpy— 6, 
also Tn and T,,, may vary from zero to two positive Valdes, ek 
being at the limit, smaller than Tay. It is therefore this limiting 
value of Tax in the abov equation which should be used in caleu- 
lating the theoretical electromotive force in place of the heat of 
combination.— C. R., xeviii, 729; J. Chem. Soc., xlvi, eb » Aug:» 
“th 
On the Color of Chemical pg 8 18m . a 4 fmetion of "the 
y nae weights of yA gh macy Elemen LLEY has 
ry 
pound, and 3d, the atomic weig t of the constituent elements. 
e first two of these conditions were studied y Ackroyd, who 
observed (1) that all chromium compounds change aler in a defi- 
