A Set of musical Glasses, such as Mr. Franklin had, of the following Dimensions

The upright of the Sides to be in the smallest ¾ of an Inch, adding a ¼ of an Inch to every larger Size, so that the upright of the largest will be 3½ Inches.

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 of 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 between their Necks to screw them hard upon, and prevent Jarring and make each Screw water-tight.