Drawing.

A screw is passed through a small hole made in the board mentioned (No. 8), and through a slit that is made for this purpose in the board underneath it (same No.), this mirror turns vertically in all directions and is held in place by the means of a nut R. When the mirror is removed from this position, the slit mentioned closes with a small board that slides between two small rails inside the machine. As for the slit mentioned (No. 10), it is partly closed by Board F when opening aperture N, and the two ends that remain open are closed by small rails.

12. On one side of the box, a rule is slid through two small irons similar to those at the back of the machine (No. 7). This rule extends a few inches behind the box and at its end has a hole through which the screw of the mirror previously mentioned is passed; so that the mirror can be tilted at all sorts of angles in front of the opening N.

13. Besides this first mirror, there is another marked L. It is smaller and attached towards its middle to a bar that passes through the middle of the top of the box. This bar can be stopped by a screw: it serves to raise or lower the mirror attached to it, so it can be fixed at all sorts of inclinations.

Remark.

Those who fear that the pipes mentioned (No. 6) are not enough to provide air to the machine can place a small bellows under the seat, which can be operated by foot. This way, the air in the machine will be continuously renewed.

Translation Notes:

- "Rule" in this context likely refers to a straight edge or guide bar used to direct parts of the apparatus.

- "Board" and "mirror" refer to specific parts of an apparatus, which are being adjusted and operated in a mechanical setup.