It is an 1888 publication of Oliver DITSON, but I rather suspect that much of it's content is a republication of a much earlier edition.
He may have updated some of the music used in the exercises.

Near the beginning is a page of illustrations, labeled "Plate 1.", showing various left hand positions and a diagram of the guitar naming it's various components.   Included in that plate is a drawing of a block of what we may assume is wood, with a fiddle peg stuck in the top, and a string tied to one side, running underneath the block, and coming up the other side to run through the peg hole.

Illustration of early guitar capo from HOLLAND Manual.

It is obviously a primitive capo.

Since there is absolutely no mention of this device in the text of the manual, it further suggests to me that in 1888 DITSON was re-using the illustration plates from an earlier edition.

For some time I have intended to get around to replicating one of these "chokers" to use on my restored "Victoria" parlor guitar.
Having been invited to perform for our local Museum provided the final impetus, and so I dug up a scrap piece of black walnut and unpacked the jig saw.   Having only the illustration to work from, I measured the width of the neck of my guitar at the 3rd fret (which is about as high as I am apt to capo up) at 2 inches, and plotted the other dimensions out on a sheet of graph paper accordingly.

Once the shapes were determined, I laid the pattern out on the wood and jigsawed them out, then drilled the 5/16" peg holes in from the center top about 5/8" then bottomed them out with a 1/4" to allow for the taper.

Prototype Chokers on Plan