How much does four fluid ounces weigh in grams or regular ounces?

Four fluid ounces of what? Four fluid ounces of Mercury weighs more than four fluid ounces of water, which weighs more than four fluid ounces of, say, fingernail-polish remover. There is a lot of confusion regarding volume and weight. Adding to the confusion is the unfortunate naming of some English units: the ounce (fluid) and the ounce (dry weight). A fluid ounce is a unit of volume, whereas the dry ounce is a unit of weight. (Compounding the insanity is the fact that there are 16 fluid ounces in a pint and 16 dry ounces in a pound. Guh!!) As it turns out, a fluid ounce of water weighs just about one dry ounce. (It weighs slightly more, actually.) But that's just water. Mercury is about 13.6 times denser than water, so one fluid ounce weighs 13.6 dry ounces!

I insist that for a long time to be suppressed forever non SI-units, but without success. American people well as peoples from several other countries remains a in a retrograde and non-rational position.