Dated May 4, 1893, Claude Johnson's British patent no. 8954 covered this left-handed brassie and its many features.  The brass disc on the top of the head, held in place by three screws, covers a "ballast chamber" where lead and/or cork discs are placed to either increase or decrease the weight of the clubhead.

As shown in one of the pictures, the cork disc at the top of the ballast chamber looks to be the original disc, installed to perfection.  I believe there are a number of metal discs underneath this cork disc as the weight of the clubhead is substantial.

The head does not have a neck, instead it has a metal ferrule.  At the base of the ferrule is a screw.  The ferrule, screw, and shaft were designed so the golfer could remove the screw and replace the shaft should it break or not fit the golfer. According to the patent, the shaft could also be keyed or screwed into place before being pinned by the screw.

This Claude Johnson brassie has its original thin greenheart shaft which is stamped with owner's initials "WR".  The original grip lacks much of the original sheepskin, but nearly all of the original underlisting remains. The Brass disc is marked "Claude Johnson's Patent / No 706 Pattern B".  The mark "No 706 Pattern B" is the production number and model of the club.  If the golfer broke the head or needed a duplicate, he or she need only refer to the production number.  

As it states in TCA2, V2: p475-476, the British Golf Museum in St. Andrews has two of these on display. 

A very special and rare club, this brassie is shown to the far left in the bottom row of the accompanying group picture.