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How To Make Armonica Glasses

Date: Uncertain
From: BF
To: Messrs. Huges & Co.
PBF: 10:180–182

We know that Franklin first hired Charles James to make his glasses. Alas, as Franklin said, he was "a very negligent, dilatory Man," and worse: he was now unable to supply one of Franklin's friends because "at length, he died suddenly."

The following would be instructions to another maker on how to make the glasses. The document is undated.

Messrs. Huges and Co. at the Cockpit Glasshouse, opposite St. Pauls'

A Set of musical Glasses, such as Mr. Franklin had, of the following Dimension [note: 1 inch = 2.54 cm]:

The upright of the Sides to be in the smallest 3/4 of an Inch [1.9 cm.], adding a 1/4 [0.6cm] of an Inch to every larger Size, so that the upright of the largest will be 3 1/2 inches [8.9cm].

Mr. Barnes is desired to take Notice, that the Glasses are not to be made hollowing up, like those Mr. Franklin had last, but like those he had first with Bottoms nearly even.

To fix them I us'd a Frame like the Figure in the Margin with an upright Iron Rod, on which was a Screw from End to End; the Rod turn'd on it's Point.

The Bottom Board had a Number of concentric Circles.

I had a Number of Brass female Screws, about an Inch long.

One of these was to be cemented in the Neck of each Glass.

On the Board I plac'd a round bit of Card a little bigger than the Neck of the Glass, then the female Screw upon that, then turn'd the Glass down with its Edge upon the Circles, then put the Screw Rod thro' the Neck of the Glass and enter'd the female Screw, and drew it up with the Card till it came into the Neck of the Glass, the Card coming close to stop the Neck; then having center'd the Glass, I pour'd in the Cement. When cold, remov'd that Glass; and plac'd another. The Neck fo the Glass should be a little warm'd, and the Cement not too hot.

When the Glasses were all furnish'd with Screws in their Necks; I put them on the Rod, a thin Piece of Cork betwen their Necks to screw them hard upon, and prevent Jarring and make each Screw water-tight.

Endorsed: Mr. Franklins directions for making a Musical Machine Mr. Franklins directions for Glasses Musical