Ivory soap is 99 and 44/100% pure what?

SHARE Ivory soap is 99 and 44/100% pure what?

Dear Cecil: There’s a question that’s been burning in the unscrubbed corners of my mind for a long time. We are told that Ivory Soap is “99 and 44/100% pure.” What’s in the other 56/100% (or if 0.56% if you prefer)? Peter Holland, Chicago


Illustration by Slug Signorino

Cecil replies:

You’re not the first to wonder. Actually it consists of “foreign and unnecessary substances,” by which I suppose they mean, for example, Dudley Moore. It all started in 1881 when Harley Procter, son of Procter & Gamble co-founder William Procter and a legendary soap salesman in his own right, decided he needed a new angle to hawk Ivory soap. Then as now people were impressed by scientific testimonials, and Harley decided if he could come up with a lab test showing Ivory was “purer” than other soaps, he’d win sales.

Trouble was, there wasn’t a standard for purity in soap, so Harley hired an independent scientific consultant in New York to concoct one. The consultant concluded that a 100% pure soap would consist of nothing but fatty acids and alkali, the somewhat yukky sounding substances that nonetheless are the chief ingredients of most soap.

That definition having been arrived at, Harley sent out some Ivory Soap for analysis and compared it with earlier analyses he’d had done of castile soap, regarded at the time as the best soap available. He was gratified to discover that by his consultant’s definition, Ivory soap was purer than the castile soaps. The impurities consisted of uncombined alkali, 0.11%; carbonates, 0.28%; and mineral matter, 0.17%. Total: 0.56%. Thinking that “99 and 44/100% pure” had just the right touch of technical authenticity to appeal to the great unwashed, so to speak, Harley began sticking the phrase in Ivory advertisements, and another classic marketing slogan was born.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.