I can’t tell if this ad is for men or women. It’s for coloring and dressing human hair. But if they are referring to a ‘little knot of hair’ in the back of the head, I’m assuming they mean those prim little buns some women wore. The Nineteenth century was all about long, curly, wavy unkempt messy buns on women!
But ladies and gentlemen, would you seriously put this solution on your head? Perhaps I shouldn’t be asking that when half the ingredients in a simple bottle of modern day shampoo can’t even be pronounced.
Ayer’s hair tonic (Please, whatever you do, do not smoke or light a match around my luxurious mane!):
(1) Dissolve 9 pounds of lead acetate in water; (2) add 9 pounds of cream of tartar, dissolved in water (as little water as will take it up); (3) wash this precipitate in water twice; (4) dissolve the precipitate in 30 pounds of solution of caustic soda (specific gravity 1.07); (5) add sufficient water to bring quantity to 13 pounds; (6) add 6 1/2 gallons of glycerine.
Seek and ye shall find almost anything on the internet. Go to this website to learn more about Ayers Hair Vigor and other hair tonics sold in the 19th century. Hair Raising Stories.