I visited the Kelsey Museum collection in the spring of 2016, went home and worked out the pattern for this hat, and then came back in the summer of 2017. At the occasion of my second visit, I took a photo of my replica beside the original. Actually I took two photos. In one of them, my replica is inside-out.
If anyone is interested, my SprangLady website contains three tutorials that take you step-by-step, showing you how to do this twining technique on a background of interlinking. And I do still have the specific pattern for this bonnet.
Progress is slow, but steady on the sprang sash.
Here is where I am. The date is now on the sash.
A reporter for the local French language newspaper stopped by to interview me. Her camera is also a video camera. She shot a short youtube video. For those who do not speak French, I explain the basic idea of sprang, two rows of cloth for every one row of work. The video then shows you a close up of the sash, and then how I move a row of work around. The sash grows from a central line outward towards the fringes.