SS ee See eee 
Self-sustaining Voltaic Battery. 53 
should ever desire. Yet though it acts vigorously when newly 
cleaned, its affinity for oxygen soon makes it worthless, This 
objection holds not only for iron, but for some kinds of batteries 
olds even against silver, and we are sent at last to the more 
noble metals. 
The difference between gold and platinum in respect to the 
adhesion, and also in respect to the liability to chemical change, 
is.so small as to make the employment of one or the other merely 
@ question of economy. But there is another property—one 
which quickly determines the preference; this is the capability 
of being put in the best mechanical form for non-adhesion, or 
making the closest approximation to atomic roughness. 
Of all the metals, platinum has the greatest teudency to the 
amorphous state, (excepting its relatives, rhodium, iridium, &c.) 
1 do not remember having seen that its crystal has ever yet been 
determined, Not so with gold, its crystalline tendency is so 
Strong, that it aggregates so much in precipitation, even from ex- 
tremely dilute solutions, that the deposit has a decidedly yellow- 
ish tinge, and the slightest pressure makes the deposit conglome- 
rate. I here need scarcely remind you of Wollaston’s tedious 
Process for metallizing spongy platinum. ae 
_ Af the above views of the nature of the adhesion are correct, 
then it follows that the surface of the conducting plate should 
tension would rise proportionally and react against the affinity ; 
the chemical action, the soul of the battery, would proportion- 
ately decline. That the mutations of the battery from adher- 
Ing coats of hydrogen, metals, or oxyds, on the conducting plate, 
ate to be attributed to conduction resistance, I shall expect will be 
Fegarded by the advocates of electro-polar forces as wholly unten- 
able, and the resistance to be considered as incompetent to 
duce the effect. But that the gas resists is indispniable, and that 
it adheres to the conducting plate is equally indisputable, for we 
Know that the very dust of the fields attracts and condenses the 
Sases; and is it not, therefore, but as fair an inference that it ad- 
