Identify this estate sale find - help!

This past weekend I attended one of my favorite kind of estate sales: a very old Washingtonian family in a very old grand house. The family bought said house during the great depression after selling their huge estate and literally never touched the house again: not paint, no adding furniture, etc.  Shabby chic would be a great term (if it wasn't already attached to something quite different). I wish I had some pictures to share with you of the house but I never thought of taking any snapshots unfortunately.

Sloans and Kenyon, a local auction house, hosts the best estate sales of the oldest families here in town. If they're hosting you know you need to be there! I had a huge haul (including literal armfuls of linens which I spent all day Sunday oxy-cleaning, laundering, and ironing) and just a few of the items are shown here in this post.

One item I purchased remains a bit of  a mystery. This small pitcher reminds me of belleek ware - the collectible paper-thin Irish porcelain, but is unsigned.

Notice it is double walled, the outer wall being pierced with a continuous inner lining.  The only marking is an S.72. and an LS scratched into the glazing. I can't figure out who made the thing.

Any idea who could have made my new treasure?