THE PROSCH RAPID SHUTTER NO. 2
Prosch Manufacturing Company, New York 1888-1892
Prosch Rapid Shutter No. 2
Introduced in 1888 and reportedly three times as fast as their Duplex Shutter, the Prosch Rapid was, per the wording in some of their advertisements, "intended for exceptionally quick work".
From Scovill's The American Annual of Photography and Photographic Times Almanac for 1888
True to form, one glance at the massive coiled spring says this shutter means business. An improved form of Prosch's Eclipse Shutter, the Rapid's reputation was built upon its most successful results, having been obtained through racetrack and athletic work.
According to Scovill & Adams' How to Make Photographs for January,1892, the Rapid Shutter had advertised speeds of 1/100th to 1/1000th of a second and was available in two sizes: the No. 1 having a 1-inch opening and the No. 2 with a 1-1/2 inch opening. The shutter had a manual release, was only capable of instantaneous exposures and had no means for adjusting the aperture. Patent No. 312,581 was granted to Cyrus Prosch on February 17, 1885. Design elements from this patent can be found in Prosch's Instantaneous, Eclipse and Rapid Shutters. The patent drawing reflects the style of the Instantaneous and Eclipse that were mounted forward of the front element, whereas the Rapid was positioned between the front and rear elements. Although configured differently, all three shutters employed a two-blade design.
Source: U.S. Patent and Trademark Office
Unlike the majority of Prosch's shutters, the Rapid Shutter No. 2 shown here has no manufacturer's name or markings, other than the number "51" found on the linkage.
Only a few examples of the Rapid probably exist, and it is among the rarest of all Prosch shutters.