c. 1850 Wiegand and Snowden Trephine Set  A complete c. 1850's trepanning set by Wiegand and Snowden of Philadelphia, Pa.   Wiegand and Snowden were partners from 1824 to 1855, located at 49 N. 7th and 49 N. 5th. Wiegand & Snowden, John Wiegand and Thomas Snowden; partnership dissolved 21 May 1855; firm continued by Thomas Snowden) surgeons' instrument makers "est. 1821" 1824-25: 49 N. 7th 1828-55: 15 N. 5th    Reference: Edmonson The rose wood case is typical for c. 1850's instrument cases.  The brass banded corners and reinforcements are also typical of the 1850's.  The swinging latches are more typical of an earlier period, and especially of sets produced in England.  The style of the trephine crown is pre-1860, but later than the vertical 'escape' style seen in the earlier example from this maker.