Waltham made this watch to compete with the center seconds chronograph watches in the English market. Almost all examples have been found in the UK. The basic ebauche is the 1872 model, but this model is a keywind with center chronograph works. It is not a true chronograph since it does not return to zero. Presumably Waltham considered it superior to the English design that stops the entire movement when the chronograph is stopped. I think the watch the English call a center seconds chronograph is actually intended as a hack watch for coordinated timing functions. From the markings they are intended for naval service. In this regard they are similar to the 4992B and related military watches in WWII.

This example is no longer in my collection, but I am looking for more. The serial number is 1,242,271. A number of runs appear in the handwritten records marked S.C.S. (the first letter is a guess but would work for Sweep Center Seconds). 1,242,101 - 150 are 4 pairs jeweled made between May 1880 and November 1881. The run with this watch is 1,242,201 - 400 with 2 pairs jeweled (pallet is not jeweled) made between May 1880 and November 1881. The runs at 1,242,501 - 700 and 1,242,801 - 900 are plain jeweled. The runs at 1,242,010, 1,242,151, 1,242,401, 1,242,701 and 1,242,901 - 1,243,000 are all marked not made. I think these  runs may be the only examples. Therefore there are 50 in 15J, 200 in 11J and 300 in 7J. Some have shown up in nice English gold cases.