Of course anything relating to horses that I see in a museum will get a second look, but this bit was not like any I have ever seen before. The only information about the bit in the display gave the time of manufacture as being in the early 1900s. Quite frankly, I am glad it is in a museum and not still being used on a horse!
Below are pictures showing the bit both from the side and from the front so you can get a view of its action in a horse's mouth. I have labeled the parts as best I could, since most of the parts were completely unfamiliar to me. If any of you knows what these odd additions to this bit are called, or how they influence the horse I would love to hear from you in the comments below.
None of those things were completely foreign to me, but the ring that attached through the top of the spade, and its bar/chain attachments have me completely baffled. I can not imagine any way that that ring and the chains could be worn outside the horse's mouth. If the ring/chains fitted inside the horse's mouth the links of the chain would rest constantly between the horse's incisor teeth when the bit is not active. When pressure is put on the shanks, the ring would lever forward jamming the chains and the bar that they hang from forward, out of the mouth. If you look at the area where the ring goes through the chain bar you can see there are chains hooked to it that connect to the shanks of the bit. This arrangement would make it impossible for the horse to spit the chains out and would pry the chain bar and attached ring downward when pressure is applied to the shanks. My best hypothesis for the purpose of the ring, dangling chains, and the bar that holds them all together is to prevent the horse from clamping its mouth shut on the bit or "getting the bit between its teeth" so to speak.
The last unusual addition to this bit are the additional chains attached to the sides of the shanks. These might be purely ornamental or they could be to discourage head tossing because they would swing and hit the horse on the side of the face when the head is thrown side to side.
Most of this is conjecture based on what I know of modern bitting. If you know better, please correct me! I would love to know how this bit was really used. It appears to be more torture device than training aid, but perhaps I am mistaken on how this worked on the horse. Please examine the photos closely and let me know what you think about this artifact.