seventy-eight of potassium unite with sixteen of oxygen. A better
name for the compound is potassium oxid: K20. The Latin name for
potassium is kalium, and K is the symbol used for an atom of that
element. If you were to purchase potassium in the form of potassium
chlorid, which in the East is often called by the old incorrect name
'muriate of potash,' the salt might be guaranteed to contain a
certain percentage of potash, which, however, consists of
eighty-three per cent. of potassium and seventeen of oxygen."

"Just what is this potassium chlorid, or 'muriate of potash'?"

"Pure potassium chlorid contains only the two elements, potassium
and chlorin."

"But didn't you say that it was guaranteed to contain potash and
that potash is part oxygen? Now you say it contains only potassium
and chlorin."

"Yes, I am sorry to say, that this is one of those blunders of our
semi-scientific ancestors for which we still suffer. The chemist
understands that the meaning of the guarantee of potash is the
amount of potash that the potassium present in the potassium chlorid
could be converted into. The best you can do is to reduce the potash
guarantee to potassium by taking eighty-three per cent. of it; or,
to be more exact, divide by ninety-four and multiply by
seventy-eight, in order to eliminate the sixteen parts of oxygen.

"It may be well to keep in mind that when the druggist says potash
he means potassium hydroxid, KOH, a compound of potassium, hydrogen,
and oxygen, as the name indicates."