Concho's eyes sparkled, but he looked doubtingly at the stranger.

"Get me some water in your pan."

Concho emptied his water bottle in his prospecting pan and handed it to
the stranger. He dipped a dried blade of grass in the bottle and then
let a drop fall from its tip in the water. The water remained unchanged.

"Now throw a little salt in the water," said the stranger.

Concho did so. Instantly a white film appeared on the surface, and
presently the whole mass assumed a milky hue.

Concho crossed himself hastily, "Mother of God, it is magic!"

"It is chloride of silver, you darned fool."

Not content with this cheap experiment, the stranger then took Concho's
breath away by reddening some litmus paper with the nitrate, and then
completely knocked over the simple Mexican by restoring its color by
dipping it in the salt water.

"You shall try me this," said Concho, offering his iron ore to the
stranger;--"you shall use the silver and the salt."

"Not so fast my friend," answered the stranger; "in the first place
this ore must be melted, and then a chip taken and put in shape like
this,--and that is worth something, my Greaser cherub. No, sir, a man
don't spend all his youth at Freiburg and Heidelburg to throw away his
science gratuitously on the first Greaser he meets."