Antique Louis Regout Maastricht Blue Onion Cup and Saucer Zwiebelmuster 1883 - 1888

This is an antique cup and saucer made in the Blue Onion pattern by Louis Regout of Maastricht, Netherlands. Louis Regout was the managing director of De Sphinx and the son of Petrus Regout, who founded De Sphinx in 1835. The R mark on the underside of each piece of this set was used between 1883 and 1888 - in 1888, the company changed its name to Mosa. The saucer measures 5 in diameter while the cup has a diameter of 3 1/2 across its top and measures 1 7/8 in height. It is in very good condition, but there is a tiny, shallow chip to the saucer edge, quite minor (see last close-up photo).
This is not a common cup and saucer as the Louis Regout factory existed with that name for only five years - wonderful quality Dutch porcelain!