The four horn playere shown in the above photo have not been identified. The hand-written date on the back of the card is 9 September 1902 and the location is Karlsbad, Bohemia.

The inscription on the back of the card identifies it as a "Souvenir of your cousin, Karl, Karlsbad, 9/9/02." Although it might appear at first glance as "22", closer inspection of the date suggests it is actually "02" (see detail below).

The two players in the center have not been identified, however the one on the left resembles Anton Horner. It is certainly possible for him to have been in Germany in the summer prior to joining the Philadelphia Orchestra in the fall of 1902. The horns  they are holding are nearly identical, except for the bracing to the leadpipe and the extra brace to the top slide on the horn at left. They are "compensating" double horns in F and B♭ probably  made in the workshop of Josef Glassl, Graslitz, Bohemia (see below).

Josef Glassl was established in Graslitz in 1898 and flourished there until after 1937. The compensating double horn shown at the right is from his 1925 catalog. In a double horn there are two sets of slides on the valves, one for the F side and the other for the B♭. In a full double horn the F slides are longer than the B♭, each being the same full length as they would be on a corresponding single horn. The thumb valve selects which set of slides are used are used for the air path. Compensating double horns have the same set of B♭ slides, however the F slides are shorter stubs whose lengths are added to the B♭ slides to make up the required lengths for the F horn. In this case the air path is directed through both sets of slides. These can be easily seen in the above photos and the engraving at the right, since the short F slide stubs are placed in front of the B♭. This arrangement is unusual and perhaps even unique since most compensating horns have the F slides hidden behind the B♭ slides.

The unidentified player on the left in the photo is holding an older German or Bohemian design single horn. It is probably in the key of F and has a terminal crook.

The unidentified player on the right of the photo somewhat resembles Max Hess who was still in Germany at the time, and later came to the United States to become principal horn of the Boston Symphony Orchestra. He is holding a Vienna horn with rotary valves which is not known to be associated with Mr. Hess, however. The horn was probably made in the workshop of Leopold Uhlmann (1806-1871) that flourished in Vienna from 1834 to 1904, or its successor, the Erste Productivgnossenschaft der Musikintrumentmacher Wien (1900-1940). The traditional Vienna horn employs dual piston valves ("Wiener pumpenventil") but this instrument is the rotary-valve model.