Henri Métert: A very early Bells and Drums music box with “mellow” bells (according to Ord-Hume)

Made about 1850, the early percussion accompaniments such as drums and bells were originally concealed underneath the bedplate.

10 bells (always playing) and a drum with ten strikers, disengageable if desired, and with adjustable loudness.

10 bells, 9 of them with two hammers allowing quickly-repeated notes to be played. The bells are playing all the time.

Mellow bells (according to Ord-Hume)
The drum has ten strikers. The drum head is vellum and the damper is a triangular shaped piece of wire. The force of the hammer strikes is very slight. This enables softly sounding, mellow bells to be used which complement the music very greatly, a quality so often list in later boxes. The drums provided with a control lever to disengage it if desired.
(Ord-Hume, Music Box, Plate 104 and 105)

The bell hammers all have adjustable heads.
The drum is provided with an extra resonating chamber, which is not to be seen in this picture.
By means of a screw the bells could be moved closer or further away from the hammers. The volume of the drum sound was adjustable to the taste of the owner, so to say more or less "mellow".
(Ord-Hume, Music Box, Plate 104 and 105)